diff --git a/llvm/lib/Target/PowerPC/TargetInfo/Makefile b/llvm/lib/Target/PowerPC/TargetInfo/Makefile
index a101aa4a4495..2d0560d275f9 100644
--- a/llvm/lib/Target/PowerPC/TargetInfo/Makefile
+++ b/llvm/lib/Target/PowerPC/TargetInfo/Makefile
@@ -10,6 +10,6 @@ LEVEL = ../../../..
 LIBRARYNAME = LLVMPowerPCInfo
 
 # Hack: we need to include 'main' target directory to grab private headers
-CPPFLAGS = -I$(PROJ_OBJ_DIR)/.. -I$(PROJ_SRC_DIR)/..
+override CPPFLAGS += -I$(PROJ_OBJ_DIR)/.. -I$(PROJ_SRC_DIR)/..
 
 include $(LEVEL)/Makefile.common