#define LdPostLibs LdPostLib XLdPostLibs
#if ImportX11
-# define TopXInclude -I$(TOP)/imports/x11/include
+# ifndef TopXInclude
+# define TopXInclude -I$(TOP)/imports/x11/include
+# endif
#elif !UseInstalledX11
# define TopXInclude -I$(TOP)/exports/include
#else