One more regex memory leak fixed.

ChangeLog

@@ -1,3 +1,9 @@
+2010-10-12  Ulrich Drepper  <drepper@redhat.com>
+
+	[BZ #12078]
+	* posix/regcomp.c (parse_branch): One more memory leak plugged.
+	* posix/bug-regex31.input: Add test case.
+
 2010-10-11  Ulrich Drepper  <drepper@gmail.com>
 
 	* posix/bug-regex31.c: Rewrite to run multiple tests from stdin.

posix/bug-regex31.input

@@ -1,3 +1,4 @@
+[[][
 ([0]
 ([0]a
 ([0]([0])

posix/regcomp.c

@@ -2160,6 +2160,8 @@ parse_branch (re_string_t *regexp, regex_t *preg, re_token_t *token,
       exp = parse_expression (regexp, preg, token, syntax, nest, err);
       if (BE (*err != REG_NOERROR && exp == NULL, 0))
 	{
+	  if (tree != NULL)
+	    postorder (tree, free_tree, NULL);
 	  return NULL;
 	}
       if (tree != NULL && exp != NULL)