diff --git a/Makefile b/Makefile
index ae5d5d4d879286e138a37af58cd64085acaffce6..4efb955c72da97aacd8aef493c0f245b665a015a 100644
--- a/Makefile
+++ b/Makefile
@@ -315,8 +315,8 @@ LDLIBS_SECURE += $(addprefix -l, $(LIBS_SECURE))
 ifeq ($(HAS_SYSTEM_PROTOBUF),false)
 ifeq ($(HAS_EMBEDDED_PROTOBUF),true)
 PROTOBUF_DEP = $(LIBDIR)/$(CONFIG)/protobuf/libprotobuf.a
-CPPFLAGS += -Ithird_party/protobuf/src
-LDFLAGS += -L$(LIBDIR)/$(CONFIG)/protobuf
+CPPFLAGS := -Ithird_party/protobuf/src $(CPPFLAGS)
+LDFLAGS := -L$(LIBDIR)/$(CONFIG)/protobuf $(LDFLAGS)
 PROTOC = $(BINDIR)/$(CONFIG)/protobuf/protoc
 else
 NO_PROTOBUF = true
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 60416525f8b9fc937105d495592be3f46c7297b5..a93e23638df1292000dce387ceb0a2e53ff8bc8b 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -332,8 +332,8 @@ LDLIBS_SECURE += $(addprefix -l, $(LIBS_SECURE))
 ifeq ($(HAS_SYSTEM_PROTOBUF),false)
 ifeq ($(HAS_EMBEDDED_PROTOBUF),true)
 PROTOBUF_DEP = $(LIBDIR)/$(CONFIG)/protobuf/libprotobuf.a
-CPPFLAGS += -Ithird_party/protobuf/src
-LDFLAGS += -L$(LIBDIR)/$(CONFIG)/protobuf
+CPPFLAGS := -Ithird_party/protobuf/src $(CPPFLAGS)
+LDFLAGS := -L$(LIBDIR)/$(CONFIG)/protobuf $(LDFLAGS)
 PROTOC = $(BINDIR)/$(CONFIG)/protobuf/protoc
 else
 NO_PROTOBUF = true