diff --git a/hw/dmx/Makefile.am b/hw/dmx/Makefile.am
index d36647b54..89136b904 100644
--- a/hw/dmx/Makefile.am
+++ b/hw/dmx/Makefile.am
@@ -16,6 +16,9 @@ GLX_INCS = -I$(top_srcdir)/hw/xfree86/dixmods/extmod \
 GLX_DEFS = @GL_CFLAGS@ 
 endif
 
+# It's essential that fbcmap.c be compiled with this flag for DMX to work!!
+DMX_CFLAGS = -DXFree86Server=1
+
 if BUILDDOCS
 SUBDIRS += doc
 endif
@@ -86,6 +89,7 @@ Xdmx_CFLAGS = \
               $(DIX_CFLAGS) \
               $(GLX_INCS) \
               $(GLX_DEFS) \
+              $(DMX_CFLAGS) \
               @DMXMODULES_CFLAGS@
 
 # Man page