Fix expandtofit() and thus getdelim() (used by SBBSecho as of Oct-29-2013)

for all builds using 32-bit longs due to numeric integer overflow as reported
by GCC ("warning: integer overflow in expression")
and MSVC ("warning C4307: '+' : integral constant overflow")
thus causing expandtofit() to always return -1 and getdelim() to always fail.

src/xpdev/filewrap.c

@@ -8,7 +8,7 @@
  * @format.tab-size 4		(Plain Text/Source Code File Header)			*
  * @format.use-tabs true	(see http://www.synchro.net/ptsc_hdr.html)		*
  *																			*
- * Copyright 2010 Rob Swindell - http://www.synchro.net/copyright.html		*
+ * Copyright 2014 Rob Swindell - http://www.synchro.net/copyright.html		*
  *																			*
  * This library is free software; you can redistribute it and/or			*
  * modify it under the terms of the GNU Lesser General Public License		*
@@ -303,7 +303,7 @@ static int expandtofit(char **linep, size_t len, size_t *linecapp)
 	char	*newline;
 	size_t	newcap;
 
-	if(len > LONG_MAX + 1)
+	if(len+1 >= LONG_MAX)
 		return -1;
 	if(len > *linecapp) {
 		if(len == LONG_MAX + 1)