Patch the old XKeycodeToKeysym call by XkbdKeycodeToKeysym

Ok, so this patch is related to this old topic : http://www.rtsoft.com/forums/showthread.php?19007-XKeycodeToKeysym-deprecated

This is rombust's solution, and it works fine on my laptop. Please let rombust check if this patch is ok before applying :)