build compiler-rt with -fPIC, otherwise the run-time libs will not link with -pie, at least on linux

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@146499 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile b/Makefile
index ef8ee5c..642b654 100644
--- a/Makefile
+++ b/Makefile
@@ -227,7 +227,7 @@
 	$(Verb) $(Tmp.CC) $(Tmp.CFLAGS) -c -o $$@ $$<
 $(Tmp.ObjPath)/%.o: $(Tmp.SrcPath)/%.c $(Tmp.Dependencies) $(Tmp.ObjPath)/.dir
 	$(Summary) "  COMPILE:   $(Tmp.Name)/$(Tmp.Config)/$(Tmp.Arch): $$<"
-	$(Verb) $(Tmp.CC) $(Tmp.CFLAGS) -c -o $$@ $$<
+	$(Verb) $(Tmp.CC) $(Tmp.CFLAGS) -c $(COMMON_CFLAGS) -o $$@ $$<
 $(Tmp.ObjPath)/%.o: $(Tmp.SrcPath)/%.cc $(Tmp.Dependencies) $(Tmp.ObjPath)/.dir
 	$(Summary) "  COMPILE:   $(Tmp.Name)/$(Tmp.Config)/$(Tmp.Arch): $$<"
 	$(Verb) $(Tmp.CC) $(Tmp.CFLAGS) -c $(COMMON_CXXFLAGS) -o $$@ $$<