$OpenBSD$

Fix crasher (double free) in sky_install_sieve

--- Source/Additions/Unicode.m.orig	Wed Mar  2 15:25:18 2011
+++ Source/Additions/Unicode.m	Wed Mar  2 15:25:23 2011
@@ -2485,7 +2485,7 @@ iconv_start:
 	}
     }
 #if	!GS_WITH_GC
-  else if (ptr != buf && (dst == 0 || ptr != *dst))
+  else if (ptr != buf && zone != 0 && (dst == 0 || ptr != *dst))
     {
       NSZoneFree(zone, ptr);
     }