The %post of the mysql rpm runs `/sbin/ldconfig -n /usr/lib/mysql` which doesn't regenerate /etc/ld.so.cache making it so that libmysqlclient.so can't be found by apache if you do an install of all of the apache, php, and mysql rpms after initial install until you manually run ldconfig to update the cache.
Bah. Is there a way to make it update the cache and not go through all of the directories? Well, I guess I'll just remove the -n.
Fixed.