diff --git a/src/vim.h b/src/vim.h
index 085f73d..05f97ba 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2109,7 +2109,7 @@
  * been seen at that stage.  But it must be before globals.h, where error_ga
  * is declared. */
 #if !defined(FEAT_GUI_W32) && !defined(FEAT_GUI_X11) \
-	&& !defined(FEAT_GUI_GTK) && !defined(FEAT_GUI_MAC)
+	&& !defined(FEAT_GUI_GTK) && !defined(FEAT_GUI_MAC) && !defined(PROTO)
 # define mch_errmsg(str)	fprintf(stderr, "%s", (str))
 # define display_errors()	fflush(stderr)
 # define mch_msg(str)		printf("%s", (str))