warning fix for !STATUS_HILITES

Avoid an unused variable complaint if compiling with STATUS_HILITES
disabled.

src/files.c

@@ -3097,6 +3097,7 @@ cnf_line_HILITE_STATUS(char *bufp)
 #ifdef STATUS_HILITES
     return parse_status_hl1(bufp, TRUE);
 #else
+    nuUse(bufp);
     return TRUE;
 #endif
 }