CXXFLAGS in examples depend on CPPFLAGS

example/echo_c++/Makefile

@@ -3,7 +3,7 @@ include $(BRPC_PATH)/config.mk
 # Notes on the flags:
 # 1. Added -fno-omit-frame-pointer: perf/tcmalloc-profiler use frame pointers by default
 # 2. Added -D__const__= : Avoid over-optimizations of TLS variables by GCC>=4.8
-CXXFLAGS = -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
+CXXFLAGS+=$(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
 HDRS+=$(BRPC_PATH)/output/include
 LIBS+=$(BRPC_PATH)/output/lib
 HDRPATHS = $(addprefix -I, $(HDRS))

example/http_c++/Makefile

@@ -4,7 +4,7 @@ include $(BRPC_PATH)/config.mk
 # Notes on the flags:
 # 1. Added -fno-omit-frame-pointer: perf/tcmalloc-profiler use frame pointers by default
 # 2. Added -D__const__= : Avoid over-optimizations of TLS variables by GCC>=4.8
-CXXFLAGS = -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
+CXXFLAGS+=$(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
 ifeq ($(NEED_GPERFTOOLS), 1)
 	CXXFLAGS+=-DBRPC_ENABLE_CPU_PROFILER
 endif

example/memcache_c++/Makefile

 BRPC_PATH = ../../
 include $(BRPC_PATH)/config.mk
-CXXFLAGS = -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -fPIC -fno-omit-frame-pointer
+CXXFLAGS+=$(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -fPIC -fno-omit-frame-pointer
 HDRS+=$(BRPC_PATH)/output/include
 LIBS+=$(BRPC_PATH)/output/lib
 HDRPATHS = $(addprefix -I, $(HDRS))

example/multi_threaded_echo_c++/Makefile

@@ -4,9 +4,9 @@ include $(BRPC_PATH)/config.mk
 # Notes on the flags:
 # 1. Added -fno-omit-frame-pointer: perf/tcmalloc-profiler use frame pointers by default
 # 2. Added -D__const__= : Avoid over-optimizations of TLS variables by GCC>=4.8
-CXXFLAGS = -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
+CXXFLAGS+=$(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -Wno-unused-parameter -fPIC -fno-omit-frame-pointer
 ifeq ($(NEED_GPERFTOOLS), 1)
-	CXXFLAGS += -DBRPC_ENABLE_CPU_PROFILER
+	CXXFLAGS+=-DBRPC_ENABLE_CPU_PROFILER
 endif
 HDRS+=$(BRPC_PATH)/output/include
 LIBS+=$(BRPC_PATH)/output/lib

example/redis_c++/Makefile

 BRPC_PATH = ../../
 include $(BRPC_PATH)/config.mk
-CXXFLAGS = -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -fPIC -fno-omit-frame-pointer
+CXXFLAGS+=$(CPPFLAGS) -std=c++0x -g -DNDEBUG -O2 -D__const__= -pipe -W -Wall -Werror -fPIC -fno-omit-frame-pointer
 HDRS+=$(BRPC_PATH)/output/include
 LIBS+=$(BRPC_PATH)/output/lib
 HDRPATHS = $(addprefix -I, $(HDRS))