Change OUT from -2 to CHAR_MIN-1, making it impossible for it to

inadvertently match a negative char in the RE being compiled.

This fixes compilation of "\376" (as an ERE) and "\376\376" (as a BRE).

PR:		84740
MFC after:	1 week

lib/libc/regex/regex2.h

@@ -196,5 +196,5 @@ struct re_guts {
 };
 
 /* misc utilities */
-#define	OUT	(-2)	/* a non-character value */
+#define	OUT	(CHAR_MIN - 1)	/* a non-character value */
 #define ISWORD(c)       (iswalnum((uch)(c)) || (c) == '_')