diff --git a/Makefile b/Makefile
index 647b163..9b7990c 100644
--- a/Makefile
+++ b/Makefile
@@ -117,10 +117,12 @@ ocamlrun: $(OCAMLRUN)
 $(BOOT)/ocamlc: $(COPY_TARGETS)
 	make -C $(OCAMLSRC)/yacc all
 	make -C miniml/interp interpopt.opt
-	./timed.sh make -C _boot/stdlib all
+	touch _boot/stdlib/.depend && make -C _boot/stdlib depend
+	touch _boot/.depend && make -C _boot depend
+	./timed.sh make -C _boot/stdlib -j$(nproc) all
 	# cd $(BOOT)/stdlib && ../../timed.sh ../../compile_stdlib.sh
 	mkdir -p $(BOOT)/compilerlibs
-	./timed.sh make -C _boot all
+	./timed.sh make -C _boot -j$(nproc) all
 	# cd $(BOOT) && ../timed.sh ../compile_ocamlc.sh
 
 .PHONY: test-compiler
diff --git a/Makefile.ocamlc b/Makefile.ocamlc
index 9be9790..5b78787 100644
--- a/Makefile.ocamlc
+++ b/Makefile.ocamlc
@@ -13,7 +13,9 @@
 #*                                                                        *
 #**************************************************************************
 
-COMPILER=../miniml/interp/interp.opt -g -nostdlib -I stdlib
+OPAQUE=-opaque
+
+COMPILER=../miniml/interp/interp.opt $(OPAQUE) -nostdlib -I stdlib
 INCLUDES=-I utils -I parsing -I typing -I bytecomp -I driver
 
 COMPFLAGS=-strict-sequence -principal -absname -w +a-4-9-41-42-44-45-48 \
@@ -21,7 +23,7 @@ COMPFLAGS=-strict-sequence -principal -absname -w +a-4-9-41-42-44-45-48 \
           -bin-annot -safe-string -strict-formats $(INCLUDES)
 LINKFLAGS=
 
-DEPEND=../miniml/interp/depend.sh
+DEPEND=../miniml/interp/depend.sh $(OPAQUE)
 DEPFLAGS=$(INCLUDES)
 
 UTILS=utils/config.cmx utils/misc.cmx \
@@ -79,8 +81,6 @@ BYTECOMP=bytecomp/instruct.cmx bytecomp/bytegen.cmx \
 
 BYTESTART=driver/main.cmx
 
-all: ocamlc
-
 # Shared parts of the system compiled with the native-code compiler
 
 compilerlibs/ocamlcommon.cmxa: $(COMMON)
diff --git a/Makefile.stdlib b/Makefile.stdlib
index 1ab9a25..bf1a615 100644
--- a/Makefile.stdlib
+++ b/Makefile.stdlib
@@ -13,14 +13,15 @@
 #*                                                                        *
 #**************************************************************************
 
-CAMLRUN = ../../ocaml-src/byterun/ocamlrun
-TARGET_BINDIR ?= $(BINDIR)
-
 COMPFLAGS=-strict-sequence -absname -w +a-4-9-41-42-44-45-48 \
           -g -warn-error A -bin-annot -nostdlib \
           -safe-string -strict-formats
-COMPILER=../../miniml/interp/interp.opt
-DEPEND=../../miniml/interp/depend.sh -native
+
+# Set -opaque for faster compilation
+OPAQUE=-opaque
+
+COMPILER=../../miniml/interp/interp.opt $(OPAQUE)
+DEPEND=../../miniml/interp/depend.sh $(OPAQUE) -native
 
 # Object file prefix
 P=stdlib__
@@ -72,10 +73,17 @@ stdlib__%.cmx: %.ml
 	$(COMPILER) $(COMPFLAGS) $(shell ./Compflags $@) -o $@ -c $<
 
 
+
 # Dependencies on Stdlib (not tracked by ocamldep)
+
 $(OTHERS:.cmx=.cmi) std_exit.cmi: stdlib.cmi
 $(OBJS) std_exit.cmx: stdlib.cmi
+ifeq "$(OPAQUE)" ""
+CMIX=cmx
 $(OTHERS) std_exit.cmx: stdlib.cmx
+else
+CMIX=cmi
+endif 
 
 clean::
 	rm -f *.cm* *.o *.a
@@ -86,12 +94,13 @@ include .depend
 EMPTY :=
 SPACE := $(EMPTY) $(EMPTY)
 
+
 .PHONY: depend
 depend:
 	$(DEPEND) $(filter-out stdlib.%,$(wildcard *.mli *.ml)) \
 	  > .depend.tmp
 	echo "stdlib.cmi : camlinternalFormatBasics.cmi" >> .depend.tmp
-	echo "stdlib.cmx : camlinternalFormatBasics.cmx" >> .depend.tmp
+	echo "stdlib.cmx : camlinternalFormatBasics.$(CMIX)" >> .depend.tmp
 	sed -Ee \
 	  's#(^| )(${subst ${SPACE},|,${PREFIXED_OBJS:stdlib__%.cmx=%}})[.]#\1stdlib__\2.#g' \
 	  .depend.tmp > .depend
diff --git a/miniml/interp/makedepend.ml b/miniml/interp/makedepend.ml
index 17b9492..b912b57 100644
--- a/miniml/interp/makedepend.ml
+++ b/miniml/interp/makedepend.ml
@@ -29,6 +29,7 @@ let load_path = ref ([] : (string * string array) list)
 let ml_synonyms = ref [".ml"]
 let mli_synonyms = ref [".mli"]
 let shared = ref false
+let opaque = ref false
 let native_only = ref false
 let bytecode_only = ref false
 let error_occurred = ref false
@@ -117,7 +118,7 @@ let find_dependency target_kind modname (byt_deps, opt_deps) =
     let basename = Filename.chop_extension filename in
     let cmi_file = basename ^ ".cmi" in
     let cmx_file = basename ^ ".cmx" in
-    let ml_exists =
+    let ml_exists = not !opaque &&
       List.exists (fun ext -> Sys.file_exists (basename ^ ext)) !ml_synonyms in
     let new_opt_dep =
       if !all_dependencies then
@@ -401,6 +402,8 @@ let main () =
         " Generate dependencies for native-code only (no .cmo files)";
      "-bytecode", Arg.Set bytecode_only,
         " Generate dependencies for bytecode-code only (no .cmx files)";
+     "-opaque", Arg.Set opaque,
+        " Generate dependencies for compilation with -opaque";
      (* "-pp", Arg.String(fun s -> Clflags.preprocessor := Some s),
          "<cmd>  Pipe sources through preprocessor <cmd>"; *)
   ] in