Added a check to make sure a player wasn't in a guild when they accepted a guild invitation. This fixes a few possible problems that could/would arise.

(Zomg. My first source commit. =x)

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@13317 54d463be-8e91-2dee-dedb-b68131a5f0ec

Changelog-Trunk.txt

@@ -3,6 +3,8 @@ Date	Added
 AS OF SVN REV. 5091, WE ARE NOW USING TRUNK.  ALL UNTESTED BUGFIXES/FEATURES GO INTO TRUNK.
 IF YOU HAVE A WORKING AND TESTED BUGFIX PUT IT INTO STABLE AS WELL AS TRUNK.
 
+2008/10/21
+	* Added a check to make sure a player wasn't in a guild when they accepted a guild invitation. [Paradox924X]
 2008/10/18
 	* Corrected a target checking problem brought about with Kaizel/Osiris combination. [SketchyPhoenix]
 2008/10/16

src/map/guild.c

@@ -677,7 +677,12 @@ int guild_reply_invite(struct map_session_data* sd, int guild_id, int flag)
 	//NOTE: this can be NULL because the person might have logged off in the meantime
 	tsd = map_id2sd(sd->guild_invite_account);
 
-	if( flag == 0 )
+	if ( sd->status.guild_id > 0 ) // [Paradox924X]
+	{ // Already in another guild.
+		if ( tsd ) clif_guild_inviteack(tsd,0);
+		return 0;
+	}
+	else if( flag == 0 )
 	{// rejected
 		sd->guild_invite = 0;
 		sd->guild_invite_account = 0;