In globcomp, use REG_NOERROR instead of literal 0

Hopefully this will make it clearer that the protocol is different than
everywhere else in ltrace, where <0 is error condition.
diff --git a/options.c b/options.c
index 004f322..a63ed28 100644
--- a/options.c
+++ b/options.c
@@ -204,7 +204,7 @@
 
 		regex_t lib_re;
 		int status = (lib_re_p ? regcomp : globcomp)(&lib_re, lib, 0);
-		if (status != 0) {
+		if (status != REG_NOERROR) {
 			char buf[100];
 			regerror(status, &lib_re, buf, sizeof buf);
 			fprintf(stderr, "Rule near '%s' will be ignored: %s.\n",