diff --git a/GL/glx/Makefile.am b/GL/glx/Makefile.am
index edec19a48..2a76e04db 100644
--- a/GL/glx/Makefile.am
+++ b/GL/glx/Makefile.am
@@ -5,6 +5,8 @@ AM_CFLAGS = $(DIX_CFLAGS)
 # none yet
 #sdk_HEADERS =
 
+INCLUDES = -I$(top_srcdir)/GL/include
+
 libglx_la_SOURCES = \
         g_disptab.c \
         g_disptab.h \