diff --git a/lib/c_glib/Makefile.am b/lib/c_glib/Makefile.am
index 4e0aa88..67ebf20 100755
--- a/lib/c_glib/Makefile.am
+++ b/lib/c_glib/Makefile.am
@@ -24,7 +24,7 @@
 lib_LTLIBRARIES = libthrift_c_glib.la
 pkgconfig_DATA = thrift_c_glib.pc
 
-AM_CFLAGS = -Isrc -I src/thrift/c_glib
+AM_CPPFLAGS = -Isrc -I src/thrift/c_glib
 
 # Define the source files for the module