--- cdecl-2.5/cdecl.c.ewt	Fri Aug  9 15:46:58 1996
+++ cdecl-2.5/cdecl.c	Fri Aug  9 15:47:06 1996
@@ -63,6 +63,7 @@
 #include <stdio.h>
 #include <ctype.h>
 #if __STDC__ || defined(DOS)
+#include <errno.h>
 # include <stdlib.h>
 # include <stddef.h>
 # include <string.h>