add a libs-only target to the clang makefile, patch by Sunay Ismail
in PR7397


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@106386 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile b/Makefile
index 17365d9..d98449e 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,11 @@
 endif
 endif
 
+ifeq ($(MAKECMDGOALS),libs-only)
+  DIRS := $(filter-out tools docs, $(DIRS))
+  OPTIONAL_DIRS :=
+endif
+
 ###
 # Common Makefile code, shared by all Clang Makefiles.
 
@@ -69,6 +74,8 @@
 
 clean::
 	@ $(MAKE) -C test clean
+	
+libs-only: all
 
 tags::
 	$(Verb) etags `find . -type f -name '*.h' -or -name '*.cpp' | \