$OpenBSD: patch-xcprint_c,v 1.2 2017/11/22 19:06:20 tb Exp $

Avoid printf "%s" NULL

merged upstream:
https://github.com/astrand/xclip/commit/26c84990d9b2b2447a4d0b55be53b715f7ddda30

Index: xcprint.c
--- xcprint.c.orig
+++ xcprint.c
@@ -86,7 +86,7 @@ errxdisplay(char *display)
     if (display == NULL)
 	display = getenv("DISPLAY");
 
-    fprintf(stderr, "Error: Can't open display: %s\n", display);
+    fprintf(stderr, "Error: Can't open display: %s\n", display ? display : "(null)");
     exit(EXIT_FAILURE);
 }
 
