delay initialization parameter illegal_substchar

Author: NathanFreeman

ext/mbstring/libmbfl/mbfl/mbfilter.c

@@ -1280,9 +1280,9 @@ mbfl_strcut(
 
 		position = device.pos;
 		(*encoder->filter_flush)(encoder);
-		illegal_substchar = (unsigned char) encoder->illegal_substchar;
 
 		if ((encoder->status && ((encoder->status & 0xF) || (encoder->status == 0x11))) || encoder->cache) {
+			illegal_substchar = (unsigned char) encoder->illegal_substchar;
 			while(device.pos > position) {
 				/* check illegal output */
 				if (device.buffer[position++] == illegal_substchar) {