filesystem: fix recursive basedir possible cyclic dependency when def…

…ault game directory uses a basedir that's base directory is undefined

That could happen when default game directory depends on base directory that don't have gameinfo.txt.
Because all game directories with liblist.gam automatically have dependency on default game directory, it causes cyclic dependency.

filesystem/filesystem.c

@@ -1199,11 +1199,11 @@ void FS_AddGameHierarchy( const char *dir, uint flags )
 	qboolean isGameDir = flags & FS_GAMEDIR_PATH;
 	char buf[MAX_VA_STRING];
 
-	GI->added = true;
-
 	if( !COM_CheckString( dir ))
 		return;
 
+	Con_Printf( "%s( %s )\n", __func__, dir );
+
 	// add the common game directory
 
 	// recursive gamedirs
@@ -1214,12 +1214,21 @@ void FS_AddGameHierarchy( const char *dir, uint flags )
 		{
 			dir = FI.games[i]->gamefolder; // fixup directory case
 
+			if( FI.games[i]->added ) // already added, refusing
+				break;
+
+			// don't add our game directory as base dir to prevent cyclic dependency
+			if( Q_stricmp( FI.games[i]->basedir, GI->gamefolder ))
+				break;
+
+			// don't add directory which basedir is equal to this gamefolder to prevent
+			// endless loop
+			if( Q_stricmp( FI.games[i]->basedir, FI.games[i]->gamefolder ))
+				break;
+
 			Con_Reportf( "%s: adding recursive basedir %s\n", __func__, FI.games[i]->basedir );
-			if( !FI.games[i]->added && Q_stricmp( FI.games[i]->gamefolder, FI.games[i]->basedir ))
-			{
-				FI.games[i]->added = true;
-				FS_AddGameHierarchy( FI.games[i]->basedir, flags & (~FS_GAMEDIR_PATH) );
-			}
+			FI.games[i]->added = true;
+			FS_AddGameHierarchy( FI.games[i]->basedir, flags & (~FS_GAMEDIR_PATH));
 			break;
 		}
 	}
@@ -1276,6 +1285,8 @@ void FS_Rescan( void )
 		FS_AddGameHierarchy( GI->basedir, 0 );
 	if( Q_stricmp( GI->basedir, GI->falldir ) && Q_stricmp( GI->gamefolder, GI->falldir ))
 		FS_AddGameHierarchy( GI->falldir, 0 );
+
+	GI->added = true;
 	FS_AddGameHierarchy( GI->gamefolder, FS_GAMEDIR_PATH );
 }