Only enable for required targets

Makefile

@@ -17,8 +17,21 @@
 
 ROOTDIR = .
 
+# The configure and *clean targets can all be run without running ./configure
+# first.
+# If no goals were specified (i.e. `make`), add defaultentry (since it requires
+# ./configure to be run)
+CAN_BE_UNCONFIGURED := $(strip \
+  $(filter-out partialclean clean distclean configure, \
+	$(if $(MAKECMDGOALS),$(MAKECMDGOALS),defaultentry)))
+
+ifeq "$(CAN_BE_UNCONFIGURED)" ""
 -include Makefile.config
 -include Makefile.common
+else
+include Makefile.config
+include Makefile.common
+endif
 
 .PHONY: defaultentry
 ifeq "$(NATIVE_COMPILER)" "true"
@@ -1079,6 +1092,8 @@ distclean: clean
 
 include .depend
 
+
+ifneq "$(strip $(CAN_BE_UNCONFIGURED))" ""
 Makefile.config Makefile.common: config.status
 
 config.status:
@@ -1092,3 +1107,4 @@ config.status:
 	@echo "	make install"
 	@echo "should work."
 	@false
+endif