diff --git a/src/doors/top/GNUmakefile b/src/doors/top/GNUmakefile
index dfc03823c7fe0f1eb04e18e95734cf8b465f33a2..3fdfc8c866842e9267a954a69b23fb228b488c50 100644
--- a/src/doors/top/GNUmakefile
+++ b/src/doors/top/GNUmakefile
@@ -8,6 +8,10 @@ ifeq ($(OS),NetBSD)
   CCFLAGS	+=	-D__unix__
 endif
 
+ifeq ($(shell if [ -f /usr/include/inttypes.h ] ; then echo YES ; fi),YES)
+ CCFLAGS	+=	-DHAS_INTTYPES_H
+endif
+
 OBJDIR	:= obj.$(OS)/
 
 vpath %.c ../../xpdev