Fix double semicolon in struct declare

Pavel discover this test case:
#include <string.h>
void test(void)
{
       struct { int foo;; } val;
       memset(&val, 0, sizeof(val));
}

Sparse ends up create a node with empty ctype in the member list.
Skip that seems fix it.

Signed-Off-By: Christopher Li<spase@chrisli.org>

Index: sparse/parse.c
===================================================================
--- sparse.orig/parse.c	2007-01-30 23:28:24.000000000 -0800
+++ sparse/parse.c	2007-01-30 23:34:21.000000000 -0800
@@ -1034,7 +1034,8 @@ static struct token *declaration_list(st
 static struct token *struct_declaration_list(struct token *token, struct symbol_list **list)
 {
 	while (!match_op(token, '}')) {
-		token = declaration_list(token, list);
+		if (!match_op(token, ';'))
+			token = declaration_list(token, list);
 		if (!match_op(token, ';')) {
 			sparse_error(token->pos, "expected ; at end of declaration");
 			break;