This makes it more likely that installed libogg and libvorbis are found, when
the user (or autoconf) specifies a different --prefix. Users who installed
their libraries in their homedir now have to set $OGG_PREFIX and $VORBIS_PREFIX,
or set their respective --with arguments.
Let the snapshot target use distcheck now that it works.
git-svn-id: https://svn.xiph.org/trunk/ezstream@12570 0101bb08-14d6-0310-b084-bc0e0c8e3800