Patch to check xcache.var_size
Right now if $wgMainCacheType (Or any of the caches) are set to CACHE_ACCEL, it only checks if the function exists. In some cases where XCache is installed however variable storage is off (xcache.var_size = 0), MediaWiki will continue to blindly try and use XCache, resulting in a slew of warnings such as this:
Warning: xcache_get(): xcache.var_size is either 0 or too small to enable var data caching in /customers/d/b/e/hugsmile.eu/httpd.www/mediawiki-1.17.0/includes/BagOStuff.php on line 619
We should probably not continue using it if there's alternatives or just plain notify the site owner that his caching method isn't working. At the least, checking for this at install time should be done. The included patch does both.
attachment xcacheFix.patch ignored as obsolete