X11 header path needs to be included in XPDEV-MT_CLFAGS, not just the

local CFLAGS.

src/xpdev/Common.gmake

@@ -137,3 +137,4 @@ else
  endif
 endif
 
+XPDEV-MT_CFLAGS	+=	-I$(X_HEADERS)

src/xpdev/GNUmakefile

@@ -12,7 +12,6 @@ ifeq ($(shell if [ -f /usr/include/alsa/asoundlib.h ] ; then echo YES ; fi),YES)
 endif
 MT_CFLAGS	+=	$(XPDEV-MT_CFLAGS)
 
-MT_CFLAGS	+=	-I$(X_HEADERS)
 ifdef WITH_SDL
  MTOBJS	+=	$(MTOBJODIR)$(DIRSEP)sdlfuncs$(OFILE)
 endif