On OpenBSD, time_t is long long.

Index: WPrefs.app/Appearance.c
--- WPrefs.app/Appearance.c.orig
+++ WPrefs.app/Appearance.c
@@ -926,7 +926,7 @@ static char *makeFileName(const char *prefix)
 		char buf[30];
 
 		wfree(fname);
-		sprintf(buf, "%08lx.cache", time(NULL));
+		sprintf(buf, "%08llx.cache", (long long)time(NULL));
 		fname = wstrconcat(prefix, buf);
 	}