Merge pull request #17624 from dankegel/issue17620-include-path-avoid-old-installed-headers

Avoid referring to old installed headers

Makefile

@@ -809,7 +809,7 @@ ifeq ($(HAS_SYSTEM_PROTOBUF),true)
 ifeq ($(HAS_PKG_CONFIG),true)
 PROTOBUF_PKG_CONFIG = true
 PC_REQUIRES_GRPCXX = protobuf
-CPPFLAGS := $(shell $(PKG_CONFIG) --cflags protobuf) $(CPPFLAGS)
+CPPFLAGS := $(CPPFLAGS) $(shell $(PKG_CONFIG) --cflags protobuf)
 LDFLAGS_PROTOBUF_PKG_CONFIG = $(shell $(PKG_CONFIG) --libs-only-L protobuf)
 ifeq ($(SYSTEM),Linux)
 ifneq ($(LDFLAGS_PROTOBUF_PKG_CONFIG),)

templates/Makefile.template

@@ -715,7 +715,7 @@
   ifeq ($(HAS_PKG_CONFIG),true)
   PROTOBUF_PKG_CONFIG = true
   PC_REQUIRES_GRPCXX = protobuf
-  CPPFLAGS := $(shell $(PKG_CONFIG) --cflags protobuf) $(CPPFLAGS)
+  CPPFLAGS := $(CPPFLAGS) $(shell $(PKG_CONFIG) --cflags protobuf)
   LDFLAGS_PROTOBUF_PKG_CONFIG = $(shell $(PKG_CONFIG) --libs-only-L protobuf)
   ifeq ($(SYSTEM),Linux)
   ifneq ($(LDFLAGS_PROTOBUF_PKG_CONFIG),)