Use regfree after we're done with preg.

From gilles@

usr.sbin/smtpd/table.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: table.c,v 1.48 2019/01/10 07:40:52 eric Exp $	*/
+/*	$OpenBSD: table.c,v 1.49 2020/12/23 08:12:14 martijn Exp $	*/
 
 /*
  * Copyright (c) 2013 Eric Faurot <eric@openbsd.org>
@@ -464,6 +464,7 @@ table_regex_match(const char *string, const char *pattern)
 {
 	regex_t preg;
 	int	cflags = REG_EXTENDED|REG_NOSUB;
+	int ret;
 
 	if (strncmp(pattern, "(?i)", 4) == 0) {
 		cflags |= REG_ICASE;
@@ -473,7 +474,11 @@ table_regex_match(const char *string, const char *pattern)
 	if (regcomp(&preg, pattern, cflags) != 0)
 		return (0);
 
-	if (regexec(&preg, string, 0, NULL, 0) != 0)
+	ret = regexec(&preg, string, 0, NULL, 0);
+
+	regfree(&preg);
+
+	if (ret != 0)
 		return (0);
 
 	return (1);