From a912ef0952c6e9c33e9613a41f29fd4af129182f Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Thu, 22 Oct 2020 18:48:06 -0700
Subject: [PATCH 1/8] can integrate later dynamic flags changes

for example `libzstd-mt` is `differentiated from `libzstd`
---
 lib/Makefile | 88 ++++++++++++++++++++++++++++++++++------------------
 1 file changed, 57 insertions(+), 31 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index 1f10c7ab..d7ce91aa 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -172,6 +172,10 @@ ZSTD_SUBDIR := common compress decompress dictBuilder legacy deprecated
 vpath %.c $(ZSTD_SUBDIR)
 
 UNAME := $(shell uname)
+
+BUILD_DIR ?= 0
+
+ifeq ($(BUILD_DIR),0)
 ifeq ($(UNAME), Darwin)
   HASH ?= md5
 endif
@@ -183,22 +187,14 @@ ifeq ($(UNAME), OpenBSD)
 endif
 HASH ?= md5sum
 
-HAVE_HASH := $(shell echo 1 | $(HASH) > /dev/null && echo 1 || echo 0)
-ifeq ($(HAVE_HASH), 1)
-  HASH_VALUE := $(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16)
-  HASH_DIR := conf_$(HASH_VALUE)
-else
-  $(info warning : could not find hash function to differentiate builds with different flags)
-  HASH_DIR := 0
+HAVE_HASH :=$(shell echo 1 | $(HASH) > /dev/null && echo 1 || echo 0)
+ifeq ($(HAVE_HASH),0)
+  $(info warning : could not find HASH ($(HASH)), needed to differentiate builds using different flags)
+  BUILD_DIR := obj/generic_noconf
 endif
+endif # $(BUILD_DIR) == 0
 
 
-BUILD_DIR ?= obj/$(HASH_DIR)
-ZSTD_DYNLIB_DIR := $(BUILD_DIR)/dynlib
-ZSTD_DYNLIB_OBJ := $(addprefix $(ZSTD_DYNLIB_DIR)/, $(ZSTD_LOCAL_OBJ))
-ZSTD_STATLIB_DIR := $(BUILD_DIR)/statlib
-ZSTD_STATLIB_OBJ := $(addprefix $(ZSTD_STATLIB_DIR)/, $(ZSTD_LOCAL_OBJ))
-
 # macOS linker doesn't support -soname, and use different extension
 # see : https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/DynamicLibraryDesignGuidelines.html
 ifeq ($(UNAME), Darwin)
@@ -223,20 +219,35 @@ lib-all: all
 
 all: lib
 
-$(ZSTD_STATLIB_DIR)/libzstd.a: ARFLAGS = rcs
-$(ZSTD_STATLIB_DIR)/libzstd.a: | $(ZSTD_STATLIB_DIR)
-$(ZSTD_STATLIB_DIR)/libzstd.a: $(ZSTD_STATLIB_OBJ)
+ifeq ($(BUILD_DIR),0)
+# determine a BUILD_DIR
+
+.PHONY: libzstd.a  # not the actual recipe
+libzstd.a:
+	$(Q)$(MAKE) $@ \
+        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
+        CPPFLAGS="$(CPPFLAGS)"
+
+else
+# $(BUILD_DIR) is defined
+
+ZSTD_STATLIB := $(BUILD_DIR)/libzstd.a
+ZSTD_STATLIB_OBJ := $(addprefix $(BUILD_DIR)/,$(ZSTD_LOCAL_OBJ))
+$(ZSTD_STATLIB): ARFLAGS = rcs
+$(ZSTD_STATLIB): | $(BUILD_DIR)
+$(ZSTD_STATLIB): $(ZSTD_STATLIB_OBJ)
 	@echo compiling static library
 	$(Q)$(AR) $(ARFLAGS) $@ $^
 
 .PHONY: libzstd.a  # must be run every time
-libzstd.a: $(ZSTD_STATLIB_DIR)/libzstd.a
+libzstd.a: $(BUILD_DIR)/libzstd.a
 	$(Q)ln -sf $< $@
 
+endif
+
 ifneq (,$(filter Windows%,$(TARGET_SYSTEM)))
 
 LIBZSTD = dll\libzstd.dll
-$(LIBZSTD):
 $(LIBZSTD): $(ZSTD_FILES)
 	@echo compiling dynamic library $(LIBVER)
 	$(CC) $(FLAGS) -DZSTD_DLL_EXPORT=1 -Wl,--out-implib,dll\libzstd.dll.a -shared $^ -o $@
@@ -244,10 +255,28 @@ $(LIBZSTD): $(ZSTD_FILES)
 else
 
 LIBZSTD = libzstd.$(SHARED_EXT_VER)
-$(ZSTD_DYNLIB_DIR)/$(LIBZSTD): CFLAGS += -fPIC
-$(ZSTD_DYNLIB_DIR)/$(LIBZSTD): LDFLAGS += -shared -fvisibility=hidden
-$(ZSTD_DYNLIB_DIR)/$(LIBZSTD): | $(ZSTD_DYNLIB_DIR)
-$(ZSTD_DYNLIB_DIR)/$(LIBZSTD): $(ZSTD_DYNLIB_OBJ)
+$(LIBZSTD): CFLAGS += -fPIC
+$(LIBZSTD): LDFLAGS += -shared -fvisibility=hidden
+
+ifeq ($(BUILD_DIR),0)
+# determine a BUILD_DIR
+
+.PHONY: $(LIBZSTD)  # not the actual recipe
+$(LIBZSTD):
+	$(Q)$(MAKE) $@ \
+        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
+        CPPFLAGS="$(CPPFLAGS)" \
+        CFLAGS="$(CFLAGS)" \
+        LDFLAGS="$(LDFLAGS)"
+
+else
+# $(BUILD_DIR) is defined
+
+ZSTD_DYNLIB := $(BUILD_DIR)/$(LIBZSTD)
+ZSTD_DYNLIB_OBJ := $(addprefix $(BUILD_DIR)/,$(ZSTD_LOCAL_OBJ))
+
+$(ZSTD_DYNLIB): | $(BUILD_DIR)
+$(ZSTD_DYNLIB): $(ZSTD_DYNLIB_OBJ)
 	@echo compiling dynamic library $(LIBVER)
 	$(Q)$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
 	@echo creating versioned links
@@ -255,10 +284,11 @@ $(ZSTD_DYNLIB_DIR)/$(LIBZSTD): $(ZSTD_DYNLIB_OBJ)
 	$(Q)ln -sf $@ libzstd.$(SHARED_EXT)
 
 .PHONY: $(LIBZSTD)  # must be run every time
-$(LIBZSTD): $(ZSTD_DYNLIB_DIR)/$(LIBZSTD)
+$(LIBZSTD): $(ZSTD_DYNLIB)
 	$(Q)ln -sf $< $@
 
-endif
+endif  # if BUILD_DIR
+endif  # if windows
 
 .PHONY: libzstd
 libzstd : $(LIBZSTD)
@@ -284,16 +314,12 @@ lib : libzstd.a libzstd
 
 DEPFLAGS = -MT $@ -MMD -MP -MF
 
-$(ZSTD_DYNLIB_DIR)/%.o : %.c $(ZSTD_DYNLIB_DIR)/%.d | $(ZSTD_DYNLIB_DIR)
+$(BUILD_DIR)/%.o : %.c $(BUILD_DIR)/%.d | $(BUILD_DIR)
 	@echo $@
-	$(Q)$(COMPILE.c) $(DEPFLAGS) $(ZSTD_DYNLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
-
-$(ZSTD_STATLIB_DIR)/%.o : %.c $(ZSTD_STATLIB_DIR)/%.d | $(ZSTD_STATLIB_DIR)
-	@echo $@
-	$(Q)$(COMPILE.c) $(DEPFLAGS) $(ZSTD_STATLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
+	$(Q)$(COMPILE.c) $(DEPFLAGS) $(BUILD_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 MKDIR ?= mkdir
-$(ZSTD_DYNLIB_DIR) $(ZSTD_STATLIB_DIR):
+$(BUILD_DIR):
 	$(Q)$(MKDIR) -p $@
 
 DEPFILES := $(ZSTD_DYNLIB_OBJ:.o=.d) $(ZSTD_STATLIB_OBJ:.o=.d)

From a7ad05bf572ee576811f4eb1a3b4adfcadd53b51 Mon Sep 17 00:00:00 2001
From: Yann Collet <yann.collet.73@gmail.com>
Date: Fri, 23 Oct 2020 10:14:04 -0700
Subject: [PATCH 2/8] fixed building libzstd with manual BUILD_DIR

and when HASH is not found
---
 lib/Makefile | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index d7ce91aa..2f6e21c2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -224,23 +224,24 @@ ifeq ($(BUILD_DIR),0)
 
 .PHONY: libzstd.a  # not the actual recipe
 libzstd.a:
-	$(Q)$(MAKE) $@ \
+	$(Q)$(MAKE) --no-print-directory $@ \
         BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
         CPPFLAGS="$(CPPFLAGS)"
 
 else
 # $(BUILD_DIR) is defined
 
-ZSTD_STATLIB := $(BUILD_DIR)/libzstd.a
-ZSTD_STATLIB_OBJ := $(addprefix $(BUILD_DIR)/,$(ZSTD_LOCAL_OBJ))
-$(ZSTD_STATLIB): ARFLAGS = rcs
-$(ZSTD_STATLIB): | $(BUILD_DIR)
+ZSTD_STATLIB_DIR := $(BUILD_DIR)/static
+ZSTD_STATLIB := $(ZSTD_STATLIB_DIR)/libzstd.a
+ZSTD_STATLIB_OBJ := $(addprefix $(ZSTD_STATLIB_DIR)/,$(ZSTD_LOCAL_OBJ))
+$(ZSTD_STATLIB): ARFLAGS ?= rcs
+$(ZSTD_STATLIB): | $(ZSTD_STATLIB_DIR)
 $(ZSTD_STATLIB): $(ZSTD_STATLIB_OBJ)
 	@echo compiling static library
 	$(Q)$(AR) $(ARFLAGS) $@ $^
 
 .PHONY: libzstd.a  # must be run every time
-libzstd.a: $(BUILD_DIR)/libzstd.a
+libzstd.a: $(ZSTD_STATLIB)
 	$(Q)ln -sf $< $@
 
 endif
@@ -263,7 +264,7 @@ ifeq ($(BUILD_DIR),0)
 
 .PHONY: $(LIBZSTD)  # not the actual recipe
 $(LIBZSTD):
-	$(Q)$(MAKE) $@ \
+	$(Q)$(MAKE) --no-print-directory $@ \
         BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
         CPPFLAGS="$(CPPFLAGS)" \
         CFLAGS="$(CFLAGS)" \
@@ -272,10 +273,11 @@ $(LIBZSTD):
 else
 # $(BUILD_DIR) is defined
 
-ZSTD_DYNLIB := $(BUILD_DIR)/$(LIBZSTD)
-ZSTD_DYNLIB_OBJ := $(addprefix $(BUILD_DIR)/,$(ZSTD_LOCAL_OBJ))
+ZSTD_DYNLIB_DIR := $(BUILD_DIR)/dynamic
+ZSTD_DYNLIB := $(ZSTD_DYNLIB_DIR)/$(LIBZSTD)
+ZSTD_DYNLIB_OBJ := $(addprefix $(ZSTD_DYNLIB_DIR)/,$(ZSTD_LOCAL_OBJ))
 
-$(ZSTD_DYNLIB): | $(BUILD_DIR)
+$(ZSTD_DYNLIB): | $(ZSTD_DYNLIB_DIR)
 $(ZSTD_DYNLIB): $(ZSTD_DYNLIB_OBJ)
 	@echo compiling dynamic library $(LIBVER)
 	$(Q)$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
@@ -314,12 +316,16 @@ lib : libzstd.a libzstd
 
 DEPFLAGS = -MT $@ -MMD -MP -MF
 
-$(BUILD_DIR)/%.o : %.c $(BUILD_DIR)/%.d | $(BUILD_DIR)
+$(ZSTD_DYNLIB_DIR)/%.o : %.c $(ZSTD_DYNLIB_DIR)/%.d | $(ZSTD_DYNLIB_DIR)
 	@echo $@
-	$(Q)$(COMPILE.c) $(DEPFLAGS) $(BUILD_DIR)/$*.d $(OUTPUT_OPTION) $<
+	$(Q)$(COMPILE.c) $(DEPFLAGS) $(ZSTD_DYNLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
+
+$(ZSTD_STATLIB_DIR)/%.o : %.c $(ZSTD_STATLIB_DIR)/%.d | $(ZSTD_STATLIB_DIR)
+	@echo $@
+	$(Q)$(COMPILE.c) $(DEPFLAGS) $(ZSTD_STATLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 MKDIR ?= mkdir
-$(BUILD_DIR):
+$(BUILD_DIR) $(ZSTD_DYNLIB_DIR) $(ZSTD_STATLIB_DIR):
 	$(Q)$(MKDIR) -p $@
 
 DEPFILES := $(ZSTD_DYNLIB_OBJ:.o=.d) $(ZSTD_STATLIB_OBJ:.o=.d)

From b5d47287138a9feb4d03c2854c90bde6ef0a87fd Mon Sep 17 00:00:00 2001
From: Yann Collet <yann.collet.73@gmail.com>
Date: Fri, 23 Oct 2020 10:22:52 -0700
Subject: [PATCH 3/8] simplified silent mode

---
 lib/Makefile | 77 ++++++++++++++++++++++++++--------------------------
 1 file changed, 39 insertions(+), 38 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index 2f6e21c2..fc9d6a6c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -8,7 +8,8 @@
 # You may select, at your option, one of the above-listed licenses.
 # ################################################################
 
-Q = $(if $(filter 1,$(V) $(VERBOSE)),,@)
+# define silent mode as default (verbose mode with V=1 or VERBOSE=1)
+$(V)$(VERBOSE).SILENT:
 
 # When cross-compiling from linux to windows,
 # you might need to specify this as "Windows."
@@ -224,7 +225,7 @@ ifeq ($(BUILD_DIR),0)
 
 .PHONY: libzstd.a  # not the actual recipe
 libzstd.a:
-	$(Q)$(MAKE) --no-print-directory $@ \
+	$(MAKE) --no-print-directory $@ \
         BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
         CPPFLAGS="$(CPPFLAGS)"
 
@@ -238,11 +239,11 @@ $(ZSTD_STATLIB): ARFLAGS ?= rcs
 $(ZSTD_STATLIB): | $(ZSTD_STATLIB_DIR)
 $(ZSTD_STATLIB): $(ZSTD_STATLIB_OBJ)
 	@echo compiling static library
-	$(Q)$(AR) $(ARFLAGS) $@ $^
+	$(AR) $(ARFLAGS) $@ $^
 
 .PHONY: libzstd.a  # must be run every time
 libzstd.a: $(ZSTD_STATLIB)
-	$(Q)ln -sf $< $@
+	ln -sf $< $@
 
 endif
 
@@ -264,7 +265,7 @@ ifeq ($(BUILD_DIR),0)
 
 .PHONY: $(LIBZSTD)  # not the actual recipe
 $(LIBZSTD):
-	$(Q)$(MAKE) --no-print-directory $@ \
+	$(MAKE) --no-print-directory $@ \
         BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
         CPPFLAGS="$(CPPFLAGS)" \
         CFLAGS="$(CFLAGS)" \
@@ -280,14 +281,14 @@ ZSTD_DYNLIB_OBJ := $(addprefix $(ZSTD_DYNLIB_DIR)/,$(ZSTD_LOCAL_OBJ))
 $(ZSTD_DYNLIB): | $(ZSTD_DYNLIB_DIR)
 $(ZSTD_DYNLIB): $(ZSTD_DYNLIB_OBJ)
 	@echo compiling dynamic library $(LIBVER)
-	$(Q)$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
+	$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
 	@echo creating versioned links
-	$(Q)ln -sf $@ libzstd.$(SHARED_EXT_MAJOR)
-	$(Q)ln -sf $@ libzstd.$(SHARED_EXT)
+	ln -sf $@ libzstd.$(SHARED_EXT_MAJOR)
+	ln -sf $@ libzstd.$(SHARED_EXT)
 
 .PHONY: $(LIBZSTD)  # must be run every time
 $(LIBZSTD): $(ZSTD_DYNLIB)
-	$(Q)ln -sf $< $@
+	ln -sf $< $@
 
 endif  # if BUILD_DIR
 endif  # if windows
@@ -318,15 +319,15 @@ DEPFLAGS = -MT $@ -MMD -MP -MF
 
 $(ZSTD_DYNLIB_DIR)/%.o : %.c $(ZSTD_DYNLIB_DIR)/%.d | $(ZSTD_DYNLIB_DIR)
 	@echo $@
-	$(Q)$(COMPILE.c) $(DEPFLAGS) $(ZSTD_DYNLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
+	$(COMPILE.c) $(DEPFLAGS) $(ZSTD_DYNLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 $(ZSTD_STATLIB_DIR)/%.o : %.c $(ZSTD_STATLIB_DIR)/%.d | $(ZSTD_STATLIB_DIR)
 	@echo $@
-	$(Q)$(COMPILE.c) $(DEPFLAGS) $(ZSTD_STATLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
+	$(COMPILE.c) $(DEPFLAGS) $(ZSTD_STATLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 MKDIR ?= mkdir
 $(BUILD_DIR) $(ZSTD_DYNLIB_DIR) $(ZSTD_STATLIB_DIR):
-	$(Q)$(MKDIR) -p $@
+	$(MKDIR) -p $@
 
 DEPFILES := $(ZSTD_DYNLIB_OBJ:.o=.d) $(ZSTD_STATLIB_OBJ:.o=.d)
 $(DEPFILES):
@@ -341,13 +342,13 @@ libzstd-nomt: LDFLAGS += -shared -fPIC -fvisibility=hidden
 libzstd-nomt: $(ZSTD_NOMT_FILES)
 	@echo compiling single-thread dynamic library $(LIBVER)
 	@echo files : $(ZSTD_NOMT_FILES)
-	$(Q)$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
+	$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
 
 clean:
-	$(Q)$(RM) -r *.dSYM   # macOS-specific
-	$(Q)$(RM) core *.o *.a *.gcda *.$(SHARED_EXT) *.$(SHARED_EXT).* libzstd.pc
-	$(Q)$(RM) dll/libzstd.dll dll/libzstd.lib libzstd-nomt*
-	$(Q)$(RM) -r obj/*
+	$(RM) -r *.dSYM   # macOS-specific
+	$(RM) core *.o *.a *.gcda *.$(SHARED_EXT) *.$(SHARED_EXT).* libzstd.pc
+	$(RM) dll/libzstd.dll dll/libzstd.lib libzstd-nomt*
+	$(RM) -r obj/*
 	@echo Cleaning library completed
 
 #-----------------------------------------------------------------------------
@@ -408,7 +409,7 @@ INSTALL_DATA    ?= $(INSTALL) -m 644
 libzstd.pc:
 libzstd.pc: libzstd.pc.in
 	@echo creating pkgconfig
-	$(Q)@sed $(SED_ERE_OPT) -e 's|@PREFIX@|$(PREFIX)|' \
+	@sed $(SED_ERE_OPT) -e 's|@PREFIX@|$(PREFIX)|' \
           -e 's|@LIBDIR@|$(PCLIBDIR)|' \
           -e 's|@INCLUDEDIR@|$(PCINCDIR)|' \
           -e 's|@VERSION@|$(VERSION)|' \
@@ -418,37 +419,37 @@ install: install-pc install-static install-shared install-includes
 	@echo zstd static and shared library installed
 
 install-pc: libzstd.pc
-	$(Q)$(INSTALL) -d -m 755 $(DESTDIR)$(PKGCONFIGDIR)/
-	$(Q)$(INSTALL_DATA) libzstd.pc $(DESTDIR)$(PKGCONFIGDIR)/
+	$(INSTALL) -d -m 755 $(DESTDIR)$(PKGCONFIGDIR)/
+	$(INSTALL_DATA) libzstd.pc $(DESTDIR)$(PKGCONFIGDIR)/
 
 install-static: libzstd.a
 	@echo Installing static library
-	$(Q)$(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
-	$(Q)$(INSTALL_DATA) libzstd.a $(DESTDIR)$(LIBDIR)
+	$(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
+	$(INSTALL_DATA) libzstd.a $(DESTDIR)$(LIBDIR)
 
 install-shared: libzstd
 	@echo Installing shared library
-	$(Q)$(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
-	$(Q)$(INSTALL_PROGRAM) $(LIBZSTD) $(DESTDIR)$(LIBDIR)
-	$(Q)ln -sf $(LIBZSTD) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT_MAJOR)
-	$(Q)ln -sf $(LIBZSTD) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT)
+	$(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
+	$(INSTALL_PROGRAM) $(LIBZSTD) $(DESTDIR)$(LIBDIR)
+	ln -sf $(LIBZSTD) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT_MAJOR)
+	ln -sf $(LIBZSTD) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT)
 
 install-includes:
 	@echo Installing includes
-	$(Q)$(INSTALL) -d -m 755 $(DESTDIR)$(INCLUDEDIR)/
-	$(Q)$(INSTALL_DATA) zstd.h $(DESTDIR)$(INCLUDEDIR)
-	$(Q)$(INSTALL_DATA) common/zstd_errors.h $(DESTDIR)$(INCLUDEDIR)
-	$(Q)$(INSTALL_DATA) dictBuilder/zdict.h $(DESTDIR)$(INCLUDEDIR)
+	$(INSTALL) -d -m 755 $(DESTDIR)$(INCLUDEDIR)/
+	$(INSTALL_DATA) zstd.h $(DESTDIR)$(INCLUDEDIR)
+	$(INSTALL_DATA) common/zstd_errors.h $(DESTDIR)$(INCLUDEDIR)
+	$(INSTALL_DATA) dictBuilder/zdict.h $(DESTDIR)$(INCLUDEDIR)
 
 uninstall:
-	$(Q)$(RM) $(DESTDIR)$(LIBDIR)/libzstd.a
-	$(Q)$(RM) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT)
-	$(Q)$(RM) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT_MAJOR)
-	$(Q)$(RM) $(DESTDIR)$(LIBDIR)/$(LIBZSTD)
-	$(Q)$(RM) $(DESTDIR)$(PKGCONFIGDIR)/libzstd.pc
-	$(Q)$(RM) $(DESTDIR)$(INCLUDEDIR)/zstd.h
-	$(Q)$(RM) $(DESTDIR)$(INCLUDEDIR)/zstd_errors.h
-	$(Q)$(RM) $(DESTDIR)$(INCLUDEDIR)/zdict.h
+	$(RM) $(DESTDIR)$(LIBDIR)/libzstd.a
+	$(RM) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT)
+	$(RM) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT_MAJOR)
+	$(RM) $(DESTDIR)$(LIBDIR)/$(LIBZSTD)
+	$(RM) $(DESTDIR)$(PKGCONFIGDIR)/libzstd.pc
+	$(RM) $(DESTDIR)$(INCLUDEDIR)/zstd.h
+	$(RM) $(DESTDIR)$(INCLUDEDIR)/zstd_errors.h
+	$(RM) $(DESTDIR)$(INCLUDEDIR)/zdict.h
 	@echo zstd libraries successfully uninstalled
 
 endif

From ffe8d9e428a2f24a1ccaf9ec6032db4930cb8b21 Mon Sep 17 00:00:00 2001
From: Yann Collet <yann.collet.73@gmail.com>
Date: Fri, 23 Oct 2020 10:27:12 -0700
Subject: [PATCH 4/8] fix partial lib test

---
 lib/Makefile                    | 4 ++--
 tests/libzstd_partial_builds.sh | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index fc9d6a6c..bc45f9b0 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -226,7 +226,7 @@ ifeq ($(BUILD_DIR),0)
 .PHONY: libzstd.a  # not the actual recipe
 libzstd.a:
 	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
+        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(ZSTD_FILES) | $(HASH) | head -c 16) \
         CPPFLAGS="$(CPPFLAGS)"
 
 else
@@ -266,7 +266,7 @@ ifeq ($(BUILD_DIR),0)
 .PHONY: $(LIBZSTD)  # not the actual recipe
 $(LIBZSTD):
 	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16) \
+        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(ZSTD_FILES) | $(HASH) | head -c 16) \
         CPPFLAGS="$(CPPFLAGS)" \
         CFLAGS="$(CFLAGS)" \
         LDFLAGS="$(LDFLAGS)"
diff --git a/tests/libzstd_partial_builds.sh b/tests/libzstd_partial_builds.sh
index b1c1e3b1..bee2dbda 100755
--- a/tests/libzstd_partial_builds.sh
+++ b/tests/libzstd_partial_builds.sh
@@ -22,7 +22,6 @@ mustBeAbsent() {
 }
 
 # default compilation : all features enabled
-make clean > /dev/null
 $ECHO "testing default library compilation"
 CFLAGS= make -C $DIR/../lib libzstd.a > $INTOVOID
 nm $DIR/../lib/libzstd.a | $GREP "\.o" > tmplog

From 89b961ea4679cda6c61287a6a7580a8d20ec0af4 Mon Sep 17 00:00:00 2001
From: Yann Collet <yann.collet.73@gmail.com>
Date: Fri, 23 Oct 2020 10:41:17 -0700
Subject: [PATCH 5/8] simplified silent mode maintenance

---
 lib/Makefile      |  7 +++--
 programs/Makefile | 71 ++++++++++++++++++++++++-----------------------
 2 files changed, 41 insertions(+), 37 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index bc45f9b0..0f502330 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -8,6 +8,9 @@
 # You may select, at your option, one of the above-listed licenses.
 # ################################################################
 
+.PHONY: default
+default: lib-release
+
 # define silent mode as default (verbose mode with V=1 or VERBOSE=1)
 $(V)$(VERBOSE).SILENT:
 
@@ -211,7 +214,7 @@ else
 endif
 
 
-.PHONY: default lib-all all clean install uninstall
+.PHONY: lib-all all clean install uninstall
 
 default: lib-release
 
@@ -235,7 +238,7 @@ else
 ZSTD_STATLIB_DIR := $(BUILD_DIR)/static
 ZSTD_STATLIB := $(ZSTD_STATLIB_DIR)/libzstd.a
 ZSTD_STATLIB_OBJ := $(addprefix $(ZSTD_STATLIB_DIR)/,$(ZSTD_LOCAL_OBJ))
-$(ZSTD_STATLIB): ARFLAGS ?= rcs
+$(ZSTD_STATLIB): ARFLAGS = rcs
 $(ZSTD_STATLIB): | $(ZSTD_STATLIB_DIR)
 $(ZSTD_STATLIB): $(ZSTD_STATLIB_OBJ)
 	@echo compiling static library
diff --git a/programs/Makefile b/programs/Makefile
index 70fb2c32..3b10af57 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -15,8 +15,12 @@
 # zstd-decompress : decompressor-only version of zstd
 # ##########################################################################
 
-# verbose mode can be triggered by V=1 or VERBOSE=1
-Q = $(if $(filter 1,$(V) $(VERBOSE)),,@)
+.PHONY: default
+default: zstd-release
+
+# silent mode by default; verbose can be triggered by V=1 or VERBOSE=1
+$(V)$(VERBOSE).SILENT:
+
 
 ZSTDDIR := ../lib
 
@@ -193,9 +197,6 @@ endif
 endif
 
 
-.PHONY: default
-default: zstd-release
-
 .PHONY: all
 all: zstd
 
@@ -207,7 +208,7 @@ $(BUILD_DIR)/zstd : $(ZSTD_OBJ)
 	@echo "$(ZLIB_MSG)"
 	@echo "$(LZMA_MSG)"
 	@echo "$(LZ4_MSG)"
-	$(Q)$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
+	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
 
 .PHONY: zstd
 zstd : CPPFLAGS += $(THREAD_CPP) $(ZLIBCPP) $(LZMACPP) $(LZ4CPP)
@@ -217,7 +218,7 @@ ifneq (,$(filter Windows%,$(OS)))
 zstd : $(RES_FILE)
 endif
 zstd : $(BUILD_DIR)/zstd
-	$(Q)ln -sf $< $@
+	ln -sf $< $@
 	@echo zstd build completed
 
 .PHONY: zstd-release
@@ -315,11 +316,11 @@ endif
 
 .PHONY: clean
 clean:
-	$(Q)$(RM) core *.o tmp* result* *.gcda dictionary *.zst \
+	$(RM) core *.o tmp* result* *.gcda dictionary *.zst \
         zstd$(EXT) zstd32$(EXT) zstd-compress$(EXT) zstd-decompress$(EXT) \
         zstd-small$(EXT) zstd-frugal$(EXT) zstd-nolegacy$(EXT) zstd4$(EXT) \
         zstd-dictBuilder$(EXT) *.gcda default*.profraw default.profdata have_zlib$(EXT)
-	$(Q)$(RM) -r obj/*
+	$(RM) -r obj/*
 	@echo Cleaning completed
 
 MD2ROFF = ronn
@@ -356,10 +357,10 @@ DEPFLAGS = -MT $@ -MMD -MP -MF
 
 $(BUILD_DIR)/%.o : %.c $(BUILD_DIR)/%.d | $(BUILD_DIR)
 	@echo $@
-	$(Q)$(COMPILE.c) $(DEPFLAGS) $(BUILD_DIR)/$*.d $(OUTPUT_OPTION) $<
+	$(COMPILE.c) $(DEPFLAGS) $(BUILD_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 MKDIR ?= mkdir
-$(BUILD_DIR): ; $(Q)$(MKDIR) -p $@
+$(BUILD_DIR): ; $(MKDIR) -p $@
 
 DEPFILES := $(ZSTD_OBJ:.o=.d)
 $(DEPFILES):
@@ -388,7 +389,7 @@ AWK = awk
 ## list: Print all targets and their descriptions (if provided)
 .PHONY: list
 list:
-	$(Q)TARGETS=$$($(MAKE) -pRrq -f $(lastword $(MAKEFILE_LIST)) : 2>/dev/null \
+	TARGETS=$$($(MAKE) -pRrq -f $(lastword $(MAKEFILE_LIST)) : 2>/dev/null \
 		| $(AWK) -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' \
 		| $(EGREP) -v  -e '^[^[:alnum:]]' | sort); \
 	{ \
@@ -436,34 +437,34 @@ INSTALL_MAN     ?= $(INSTALL_DATA)
 .PHONY: install
 install: zstd
 	@echo Installing binaries
-	$(Q)$(INSTALL) -d -m 755 $(DESTDIR)$(BINDIR)/ $(DESTDIR)$(MAN1DIR)/
-	$(Q)$(INSTALL_PROGRAM) zstd$(EXT) $(DESTDIR)$(BINDIR)/zstd$(EXT)
-	$(Q)ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdcat$(EXT)
-	$(Q)ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/unzstd$(EXT)
-	$(Q)ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdmt$(EXT)
-	$(Q)$(INSTALL_SCRIPT) zstdless $(DESTDIR)$(BINDIR)/zstdless
-	$(Q)$(INSTALL_SCRIPT) zstdgrep $(DESTDIR)$(BINDIR)/zstdgrep
+	$(INSTALL) -d -m 755 $(DESTDIR)$(BINDIR)/ $(DESTDIR)$(MAN1DIR)/
+	$(INSTALL_PROGRAM) zstd$(EXT) $(DESTDIR)$(BINDIR)/zstd$(EXT)
+	ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdcat$(EXT)
+	ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/unzstd$(EXT)
+	ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdmt$(EXT)
+	$(INSTALL_SCRIPT) zstdless $(DESTDIR)$(BINDIR)/zstdless
+	$(INSTALL_SCRIPT) zstdgrep $(DESTDIR)$(BINDIR)/zstdgrep
 	@echo Installing man pages
-	$(Q)$(INSTALL_MAN) zstd.1 $(DESTDIR)$(MAN1DIR)/zstd.1
-	$(Q)ln -sf zstd.1 $(DESTDIR)$(MAN1DIR)/zstdcat.1
-	$(Q)ln -sf zstd.1 $(DESTDIR)$(MAN1DIR)/unzstd.1
-	$(Q)$(INSTALL_MAN) zstdgrep.1 $(DESTDIR)$(MAN1DIR)/zstdgrep.1
-	$(Q)$(INSTALL_MAN) zstdless.1 $(DESTDIR)$(MAN1DIR)/zstdless.1
+	$(INSTALL_MAN) zstd.1 $(DESTDIR)$(MAN1DIR)/zstd.1
+	ln -sf zstd.1 $(DESTDIR)$(MAN1DIR)/zstdcat.1
+	ln -sf zstd.1 $(DESTDIR)$(MAN1DIR)/unzstd.1
+	$(INSTALL_MAN) zstdgrep.1 $(DESTDIR)$(MAN1DIR)/zstdgrep.1
+	$(INSTALL_MAN) zstdless.1 $(DESTDIR)$(MAN1DIR)/zstdless.1
 	@echo zstd installation completed
 
 .PHONY: uninstall
 uninstall:
-	$(Q)$(RM) $(DESTDIR)$(BINDIR)/zstdgrep
-	$(Q)$(RM) $(DESTDIR)$(BINDIR)/zstdless
-	$(Q)$(RM) $(DESTDIR)$(BINDIR)/zstdcat
-	$(Q)$(RM) $(DESTDIR)$(BINDIR)/unzstd
-	$(Q)$(RM) $(DESTDIR)$(BINDIR)/zstdmt
-	$(Q)$(RM) $(DESTDIR)$(BINDIR)/zstd
-	$(Q)$(RM) $(DESTDIR)$(MAN1DIR)/zstdless.1
-	$(Q)$(RM) $(DESTDIR)$(MAN1DIR)/zstdgrep.1
-	$(Q)$(RM) $(DESTDIR)$(MAN1DIR)/zstdcat.1
-	$(Q)$(RM) $(DESTDIR)$(MAN1DIR)/unzstd.1
-	$(Q)$(RM) $(DESTDIR)$(MAN1DIR)/zstd.1
+	$(RM) $(DESTDIR)$(BINDIR)/zstdgrep
+	$(RM) $(DESTDIR)$(BINDIR)/zstdless
+	$(RM) $(DESTDIR)$(BINDIR)/zstdcat
+	$(RM) $(DESTDIR)$(BINDIR)/unzstd
+	$(RM) $(DESTDIR)$(BINDIR)/zstdmt
+	$(RM) $(DESTDIR)$(BINDIR)/zstd
+	$(RM) $(DESTDIR)$(MAN1DIR)/zstdless.1
+	$(RM) $(DESTDIR)$(MAN1DIR)/zstdgrep.1
+	$(RM) $(DESTDIR)$(MAN1DIR)/zstdcat.1
+	$(RM) $(DESTDIR)$(MAN1DIR)/unzstd.1
+	$(RM) $(DESTDIR)$(MAN1DIR)/zstd.1
 	@echo zstd programs successfully uninstalled
 
 endif

From a6ee614a44f2e61ee6d3396b144c04847705f22f Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Fri, 23 Oct 2020 16:08:21 -0700
Subject: [PATCH 6/8] make zstd is now differentiated from zstd-nomt

avoids mixing object files using different flags
---
 lib/Makefile      | 11 +++++------
 programs/Makefile | 46 ++++++++++++++++++++++++++++++----------------
 2 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index 0f502330..39781ddd 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -182,15 +182,14 @@ BUILD_DIR ?= 0
 ifeq ($(BUILD_DIR),0)
 ifeq ($(UNAME), Darwin)
   HASH ?= md5
-endif
-ifeq ($(UNAME), FreeBSD)
+else ifeq ($(UNAME), FreeBSD)
   HASH ?= gmd5sum
-endif
-ifeq ($(UNAME), OpenBSD)
+else ifeq ($(UNAME), OpenBSD)
   HASH ?= md5
 endif
 HASH ?= md5sum
 
+HASH_DIR = conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(ZSTD_FILES) | $(HASH) | head -c 16)
 HAVE_HASH :=$(shell echo 1 | $(HASH) > /dev/null && echo 1 || echo 0)
 ifeq ($(HAVE_HASH),0)
   $(info warning : could not find HASH ($(HASH)), needed to differentiate builds using different flags)
@@ -229,7 +228,7 @@ ifeq ($(BUILD_DIR),0)
 .PHONY: libzstd.a  # not the actual recipe
 libzstd.a:
 	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(ZSTD_FILES) | $(HASH) | head -c 16) \
+        BUILD_DIR=obj/$(HASH_DIR) \
         CPPFLAGS="$(CPPFLAGS)"
 
 else
@@ -269,7 +268,7 @@ ifeq ($(BUILD_DIR),0)
 .PHONY: $(LIBZSTD)  # not the actual recipe
 $(LIBZSTD):
 	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(ZSTD_FILES) | $(HASH) | head -c 16) \
+        BUILD_DIR=obj/$(HASH_DIR) \
         CPPFLAGS="$(CPPFLAGS)" \
         CFLAGS="$(CFLAGS)" \
         LDFLAGS="$(LDFLAGS)"
diff --git a/programs/Makefile b/programs/Makefile
index 3b10af57..ce3c83ad 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -98,28 +98,25 @@ ZSTD_ALL_SRC := $(ZSTDLIB_LOCAL_SRC) $(ZSTD_CLI_SRC)
 ZSTD_ALL_OBJ := $(ZSTD_ALL_SRC:.c=.o)
 
 UNAME := $(shell uname)
+BUILD_DIR ?= 0
+
+ifeq ($(BUILD_DIR),0)
 ifeq ($(UNAME), Darwin)
   HASH ?= md5
-endif
-ifeq ($(UNAME), FreeBSD)
+else ifeq ($(UNAME), FreeBSD)
   HASH ?= gmd5sum
-endif
-ifeq ($(UNAME), OpenBSD)
+else ifeq ($(UNAME), OpenBSD)
   HASH ?= md5
 endif
 HASH ?= md5sum
 
-HAVE_HASH := $(shell echo 1 | $(HASH) > /dev/null && echo 1 || echo 0)
-ifeq ($(HAVE_HASH), 1)
-  HASH_VALUE := $(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) | $(HASH) | head -c 16)
-  HASH_DIR := conf_$(HASH_VALUE)
-else
-  $(info warning : could not find hash function to differentiate builds with different flags)
-  HASH_DIR := 0
+HASH_DIR = conf_$(shell echo $(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) $(ZSTD_FILES) | $(HASH) | head -c 16)
+HAVE_HASH :=$(shell echo 1 | $(HASH) > /dev/null && echo 1 || echo 0)
+ifeq ($(HAVE_HASH),0)
+  $(info warning : could not find HASH ($(HASH)), needed to differentiate builds using different flags)
+  BUILD_DIR := obj/generic_noconf
 endif
-
-BUILD_DIR ?= obj/$(HASH_DIR)
-ZSTD_OBJ := $(addprefix $(BUILD_DIR)/, $(ZSTD_ALL_OBJ))
+endif # $(BUILD_DIR) == 0
 
 # Define *.exe as extension for Windows systems
 ifneq (,$(filter Windows%,$(OS)))
@@ -203,6 +200,7 @@ all: zstd
 .PHONY: allVariants
 allVariants: zstd zstd-compress zstd-decompress zstd-small zstd-nolegacy zstd-dictBuilder
 
+ZSTD_OBJ := $(addprefix $(BUILD_DIR)/, $(ZSTD_ALL_OBJ))
 $(BUILD_DIR)/zstd : $(ZSTD_OBJ)
 	@echo "$(THREAD_MSG)"
 	@echo "$(ZLIB_MSG)"
@@ -210,17 +208,34 @@ $(BUILD_DIR)/zstd : $(ZSTD_OBJ)
 	@echo "$(LZ4_MSG)"
 	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
 
-.PHONY: zstd
+.PHONY: zstd  # must always be run
 zstd : CPPFLAGS += $(THREAD_CPP) $(ZLIBCPP) $(LZMACPP) $(LZ4CPP)
 zstd : LDFLAGS += $(THREAD_LD) $(ZLIBLD) $(LZMALD) $(LZ4LD) $(DEBUGFLAGS_LD)
 zstd : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
 ifneq (,$(filter Windows%,$(OS)))
 zstd : $(RES_FILE)
 endif
+
+ifeq ($(BUILD_DIR),0)
+# generate a BUILD_DIR from flags
+
+zstd:
+	$(MAKE) --no-print-directory $@ \
+        BUILD_DIR=obj/$(HASH_DIR) \
+        CPPFLAGS="$(CPPFLAGS)" \
+        CFLAGS="$(CFLAGS)" \
+        LDFLAGS="$(LDFLAGS)"
+
+else
+# BUILD_DIR is defined
+
 zstd : $(BUILD_DIR)/zstd
 	ln -sf $< $@
 	@echo zstd build completed
 
+endif
+
+
 .PHONY: zstd-release
 zstd-release: DEBUGFLAGS := -DBACKTRACE_ENABLE=0
 zstd-release: DEBUGFLAGS_LD :=
@@ -372,7 +387,6 @@ include $(wildcard $(DEPFILES))
 #-----------------------------------------------------------------------------
 # make install is validated only for Linux, macOS, BSD, Hurd and Solaris targets
 #-----------------------------------------------------------------------------
-UNAME := $(shell uname)
 ifneq (,$(filter $(UNAME),Linux Darwin GNU/kFreeBSD GNU OpenBSD FreeBSD NetBSD DragonFly SunOS Haiku))
 
 HAVE_COLORNEVER = $(shell echo a | egrep --color=never a > /dev/null 2> /dev/null && echo 1 || echo 0)

From 456db0c3770856ea83de771b98fb6715fa4fb13a Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Fri, 23 Oct 2020 16:46:49 -0700
Subject: [PATCH 7/8] make install only rebuild binaries if they don't exist

Now `make` followed by `make install` doesn't rebuild binaries

also : only generated target directories if they don't already exist
---
 lib/Makefile      | 20 ++++++++++++--------
 programs/Makefile | 10 +++++++---
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index 39781ddd..a549b82b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -320,11 +320,11 @@ lib : libzstd.a libzstd
 DEPFLAGS = -MT $@ -MMD -MP -MF
 
 $(ZSTD_DYNLIB_DIR)/%.o : %.c $(ZSTD_DYNLIB_DIR)/%.d | $(ZSTD_DYNLIB_DIR)
-	@echo $@
+	@echo CC $@
 	$(COMPILE.c) $(DEPFLAGS) $(ZSTD_DYNLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 $(ZSTD_STATLIB_DIR)/%.o : %.c $(ZSTD_STATLIB_DIR)/%.d | $(ZSTD_STATLIB_DIR)
-	@echo $@
+	@echo CC $@
 	$(COMPILE.c) $(DEPFLAGS) $(ZSTD_STATLIB_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 MKDIR ?= mkdir
@@ -421,24 +421,28 @@ install: install-pc install-static install-shared install-includes
 	@echo zstd static and shared library installed
 
 install-pc: libzstd.pc
-	$(INSTALL) -d -m 755 $(DESTDIR)$(PKGCONFIGDIR)/
+	[ -e $(DESTDIR)$(PKGCONFIGDIR) ] || $(INSTALL) -d -m 755 $(DESTDIR)$(PKGCONFIGDIR)/
 	$(INSTALL_DATA) libzstd.pc $(DESTDIR)$(PKGCONFIGDIR)/
 
-install-static: libzstd.a
+install-static:
+	# only generate libzstd.a if it's not already present
+	[ -e libzstd.a ] || $(MAKE) libzstd.a-release
+	[ -e $(DESTDIR)$(LIBDIR) ] || $(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
 	@echo Installing static library
-	$(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
 	$(INSTALL_DATA) libzstd.a $(DESTDIR)$(LIBDIR)
 
-install-shared: libzstd
+install-shared:
+	# only generate libzstd.so if it's not already present
+	[ -e $(LIBZSTD) ] || $(MAKE) libzstd-release
+	[ -e $(DESTDIR)$(LIBDIR) ] || $(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
 	@echo Installing shared library
-	$(INSTALL) -d -m 755 $(DESTDIR)$(LIBDIR)/
 	$(INSTALL_PROGRAM) $(LIBZSTD) $(DESTDIR)$(LIBDIR)
 	ln -sf $(LIBZSTD) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT_MAJOR)
 	ln -sf $(LIBZSTD) $(DESTDIR)$(LIBDIR)/libzstd.$(SHARED_EXT)
 
 install-includes:
+	[ -e $(DESTDIR)$(INCLUDEDIR) ] || $(INSTALL) -d -m 755 $(DESTDIR)$(INCLUDEDIR)/
 	@echo Installing includes
-	$(INSTALL) -d -m 755 $(DESTDIR)$(INCLUDEDIR)/
 	$(INSTALL_DATA) zstd.h $(DESTDIR)$(INCLUDEDIR)
 	$(INSTALL_DATA) common/zstd_errors.h $(DESTDIR)$(INCLUDEDIR)
 	$(INSTALL_DATA) dictBuilder/zdict.h $(DESTDIR)$(INCLUDEDIR)
diff --git a/programs/Makefile b/programs/Makefile
index ce3c83ad..e9ba02cd 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -206,6 +206,7 @@ $(BUILD_DIR)/zstd : $(ZSTD_OBJ)
 	@echo "$(ZLIB_MSG)"
 	@echo "$(LZMA_MSG)"
 	@echo "$(LZ4_MSG)"
+	@echo LINK $@
 	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
 
 .PHONY: zstd  # must always be run
@@ -371,7 +372,7 @@ preview-man: clean-man man
 DEPFLAGS = -MT $@ -MMD -MP -MF
 
 $(BUILD_DIR)/%.o : %.c $(BUILD_DIR)/%.d | $(BUILD_DIR)
-	@echo $@
+	@echo CC $@
 	$(COMPILE.c) $(DEPFLAGS) $(BUILD_DIR)/$*.d $(OUTPUT_OPTION) $<
 
 MKDIR ?= mkdir
@@ -449,9 +450,12 @@ INSTALL_DATA    ?= $(INSTALL) -m 644
 INSTALL_MAN     ?= $(INSTALL_DATA)
 
 .PHONY: install
-install: zstd
+install:
+	# generate zstd only if not already present
+	[ -e zstd ] || $(MAKE) zstd-release
+	[ -e $(DESTDIR)$(BINDIR) ] || $(INSTALL) -d -m 755 $(DESTDIR)$(BINDIR)/
+	[ -e $(DESTDIR)$(MAN1DIR) ] || $(INSTALL) -d -m 755 $(DESTDIR)$(MAN1DIR)/
 	@echo Installing binaries
-	$(INSTALL) -d -m 755 $(DESTDIR)$(BINDIR)/ $(DESTDIR)$(MAN1DIR)/
 	$(INSTALL_PROGRAM) zstd$(EXT) $(DESTDIR)$(BINDIR)/zstd$(EXT)
 	ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdcat$(EXT)
 	ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/unzstd$(EXT)

From f6ecf1568f147b13b30646aa5ee7342763382c38 Mon Sep 17 00:00:00 2001
From: Yann Collet <yann.collet.73@gmail.com>
Date: Wed, 28 Oct 2020 09:39:15 -0700
Subject: [PATCH 8/8] minor Makefile refactor

hopefully improving readability
---
 lib/Makefile      | 61 +++++++++++++++++++++--------------------------
 programs/Makefile | 52 +++++++++++++++++++++-------------------
 2 files changed, 54 insertions(+), 59 deletions(-)

diff --git a/lib/Makefile b/lib/Makefile
index a549b82b..c6197e2d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -15,12 +15,9 @@ default: lib-release
 $(V)$(VERBOSE).SILENT:
 
 # When cross-compiling from linux to windows,
-# you might need to specify this as "Windows."
-# Fedora build fails without it.
-#
-# Note: mingw-w64 build from linux to windows
-# does not fail on other tested distros (ubuntu, debian)
-# even without manually specifying the TARGET_SYSTEM.
+# one might need to specify TARGET_SYSTEM as "Windows."
+# Building from Fedora fails without it.
+# (but Ubuntu and Debian don't need to set anything)
 TARGET_SYSTEM ?= $(OS)
 
 # Version numbers
@@ -35,8 +32,8 @@ LIBVER := $(shell echo $(LIBVER_SCRIPT))
 VERSION?= $(LIBVER)
 CCVER := $(shell $(CC) --version)
 
-# This is a helper variable that configures a bunch of other variables to new,
-# space-optimized defaults.
+# ZSTD_LIB_MINIFY is a helper variable that
+# configures a bunch of other variables to space-optimized defaults.
 ZSTD_LIB_MINIFY ?= 0
 ifneq ($(ZSTD_LIB_MINIFY), 0)
   HAVE_CC_OZ ?= $(shell echo "" | $(CC) -Oz -x c -c - -o /dev/null 2> /dev/null && echo 1 || echo 0)
@@ -177,9 +174,7 @@ vpath %.c $(ZSTD_SUBDIR)
 
 UNAME := $(shell uname)
 
-BUILD_DIR ?= 0
-
-ifeq ($(BUILD_DIR),0)
+ifndef BUILD_DIR
 ifeq ($(UNAME), Darwin)
   HASH ?= md5
 else ifeq ($(UNAME), FreeBSD)
@@ -195,7 +190,7 @@ ifeq ($(HAVE_HASH),0)
   $(info warning : could not find HASH ($(HASH)), needed to differentiate builds using different flags)
   BUILD_DIR := obj/generic_noconf
 endif
-endif # $(BUILD_DIR) == 0
+endif # BUILD_DIR
 
 
 # macOS linker doesn't support -soname, and use different extension
@@ -212,27 +207,31 @@ else
   SHARED_EXT_VER = $(SHARED_EXT).$(LIBVER)
 endif
 
+SET_CACHE_DIRECTORY = \
+	$(MAKE) --no-print-directory $@ \
+    BUILD_DIR=obj/$(HASH_DIR) \
+    CPPFLAGS="$(CPPFLAGS)" \
+    CFLAGS="$(CFLAGS)" \
+    LDFLAGS="$(LDFLAGS)"
+
 
 .PHONY: lib-all all clean install uninstall
 
-default: lib-release
-
 # alias
 lib-all: all
 
 all: lib
 
-ifeq ($(BUILD_DIR),0)
-# determine a BUILD_DIR
+.PHONY: libzstd.a  # must be run every time
+
+ifndef BUILD_DIR
+# determine BUILD_DIR from compilation flags
 
-.PHONY: libzstd.a  # not the actual recipe
 libzstd.a:
-	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/$(HASH_DIR) \
-        CPPFLAGS="$(CPPFLAGS)"
+	$(SET_CACHE_DIRECTORY)
 
 else
-# $(BUILD_DIR) is defined
+# BUILD_DIR is defined
 
 ZSTD_STATLIB_DIR := $(BUILD_DIR)/static
 ZSTD_STATLIB := $(ZSTD_STATLIB_DIR)/libzstd.a
@@ -243,7 +242,6 @@ $(ZSTD_STATLIB): $(ZSTD_STATLIB_OBJ)
 	@echo compiling static library
 	$(AR) $(ARFLAGS) $@ $^
 
-.PHONY: libzstd.a  # must be run every time
 libzstd.a: $(ZSTD_STATLIB)
 	ln -sf $< $@
 
@@ -256,25 +254,21 @@ $(LIBZSTD): $(ZSTD_FILES)
 	@echo compiling dynamic library $(LIBVER)
 	$(CC) $(FLAGS) -DZSTD_DLL_EXPORT=1 -Wl,--out-implib,dll\libzstd.dll.a -shared $^ -o $@
 
-else
+else  # not Windows
 
 LIBZSTD = libzstd.$(SHARED_EXT_VER)
+.PHONY: $(LIBZSTD)  # must be run every time
 $(LIBZSTD): CFLAGS += -fPIC
 $(LIBZSTD): LDFLAGS += -shared -fvisibility=hidden
 
-ifeq ($(BUILD_DIR),0)
-# determine a BUILD_DIR
+ifndef BUILD_DIR
+# determine BUILD_DIR from compilation flags
 
-.PHONY: $(LIBZSTD)  # not the actual recipe
 $(LIBZSTD):
-	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/$(HASH_DIR) \
-        CPPFLAGS="$(CPPFLAGS)" \
-        CFLAGS="$(CFLAGS)" \
-        LDFLAGS="$(LDFLAGS)"
+	$(SET_CACHE_DIRECTORY)
 
 else
-# $(BUILD_DIR) is defined
+# BUILD_DIR is defined
 
 ZSTD_DYNLIB_DIR := $(BUILD_DIR)/dynamic
 ZSTD_DYNLIB := $(ZSTD_DYNLIB_DIR)/$(LIBZSTD)
@@ -288,11 +282,10 @@ $(ZSTD_DYNLIB): $(ZSTD_DYNLIB_OBJ)
 	ln -sf $@ libzstd.$(SHARED_EXT_MAJOR)
 	ln -sf $@ libzstd.$(SHARED_EXT)
 
-.PHONY: $(LIBZSTD)  # must be run every time
 $(LIBZSTD): $(ZSTD_DYNLIB)
 	ln -sf $< $@
 
-endif  # if BUILD_DIR
+endif  # ifndef BUILD_DIR
 endif  # if windows
 
 .PHONY: libzstd
diff --git a/programs/Makefile b/programs/Makefile
index e9ba02cd..3443014c 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -98,9 +98,8 @@ ZSTD_ALL_SRC := $(ZSTDLIB_LOCAL_SRC) $(ZSTD_CLI_SRC)
 ZSTD_ALL_OBJ := $(ZSTD_ALL_SRC:.c=.o)
 
 UNAME := $(shell uname)
-BUILD_DIR ?= 0
 
-ifeq ($(BUILD_DIR),0)
+ifndef BUILD_DIR
 ifeq ($(UNAME), Darwin)
   HASH ?= md5
 else ifeq ($(UNAME), FreeBSD)
@@ -116,7 +115,7 @@ ifeq ($(HAVE_HASH),0)
   $(info warning : could not find HASH ($(HASH)), needed to differentiate builds using different flags)
   BUILD_DIR := obj/generic_noconf
 endif
-endif # $(BUILD_DIR) == 0
+endif # BUILD_DIR
 
 # Define *.exe as extension for Windows systems
 ifneq (,$(filter Windows%,$(OS)))
@@ -193,6 +192,13 @@ ifeq ($(BACKTRACE), 1)
 endif
 endif
 
+SET_CACHE_DIRECTORY = \
+	$(MAKE) --no-print-directory $@ \
+    BUILD_DIR=obj/$(HASH_DIR) \
+    CPPFLAGS="$(CPPFLAGS)" \
+    CFLAGS="$(CFLAGS)" \
+    LDFLAGS="$(LDFLAGS)"
+
 
 .PHONY: all
 all: zstd
@@ -200,6 +206,23 @@ all: zstd
 .PHONY: allVariants
 allVariants: zstd zstd-compress zstd-decompress zstd-small zstd-nolegacy zstd-dictBuilder
 
+.PHONY: zstd  # must always be run
+zstd : CPPFLAGS += $(THREAD_CPP) $(ZLIBCPP) $(LZMACPP) $(LZ4CPP)
+zstd : LDFLAGS += $(THREAD_LD) $(ZLIBLD) $(LZMALD) $(LZ4LD) $(DEBUGFLAGS_LD)
+zstd : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
+ifneq (,$(filter Windows%,$(OS)))
+zstd : $(RES_FILE)
+endif
+
+ifndef BUILD_DIR
+# generate BUILD_DIR from flags
+
+zstd:
+	$(SET_CACHE_DIRECTORY)
+
+else
+# BUILD_DIR is defined
+
 ZSTD_OBJ := $(addprefix $(BUILD_DIR)/, $(ZSTD_ALL_OBJ))
 $(BUILD_DIR)/zstd : $(ZSTD_OBJ)
 	@echo "$(THREAD_MSG)"
@@ -209,32 +232,11 @@ $(BUILD_DIR)/zstd : $(ZSTD_OBJ)
 	@echo LINK $@
 	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
 
-.PHONY: zstd  # must always be run
-zstd : CPPFLAGS += $(THREAD_CPP) $(ZLIBCPP) $(LZMACPP) $(LZ4CPP)
-zstd : LDFLAGS += $(THREAD_LD) $(ZLIBLD) $(LZMALD) $(LZ4LD) $(DEBUGFLAGS_LD)
-zstd : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
-ifneq (,$(filter Windows%,$(OS)))
-zstd : $(RES_FILE)
-endif
-
-ifeq ($(BUILD_DIR),0)
-# generate a BUILD_DIR from flags
-
-zstd:
-	$(MAKE) --no-print-directory $@ \
-        BUILD_DIR=obj/$(HASH_DIR) \
-        CPPFLAGS="$(CPPFLAGS)" \
-        CFLAGS="$(CFLAGS)" \
-        LDFLAGS="$(LDFLAGS)"
-
-else
-# BUILD_DIR is defined
-
 zstd : $(BUILD_DIR)/zstd
 	ln -sf $< $@
 	@echo zstd build completed
 
-endif
+endif  # BUILD_DIR
 
 
 .PHONY: zstd-release