--- Makefile.orig	2015-10-25 13:13:52 UTC
+++ Makefile
@@ -1043,7 +1043,7 @@ ifeq ($(USE_VOIP),1)
   CLIENT_CFLAGS += -DUSE_VOIP
   SERVER_CFLAGS += -DUSE_VOIP
   ifeq ($(USE_INTERNAL_SPEEX),1)
-    CLIENT_CFLAGS += -DFLOATING_POINT -DUSE_ALLOCA -I$(SPEEXDIR)/include
+    CLIENT_CFLAGS := -I$(SPEEXDIR)/include -DFLOATING_POINT -DUSE_ALLOCA $(CLIENT_CFLAGS)
   else
     CLIENT_LIBS += -lspeex -lspeexdsp
   endif
