* Revert the Quartz disabling.

(ie. most) automake users are used to.
If you DO want NOT to use maintainer mode you are free to pass
--disable-maintainer-mode to configure.

    __ppc64__ (meaning PowerPC).

    with --disable-decoder.

  * extras/contrib/src/Makefile: re-added --disable-codec flags (the FFMPEG
    tree on altair was outdated) but removed the duplicate vorbis one.

    there is no easy way to check for the presence of an executable, but
    trying to execute it ("foo --version >/dev/null") is usually safe.

    code.

* A few Mac OS X intf fixes. To be honest. we should rewrite the thing from scratch. it's a mess... 

* Disable the non functional QT/Quartz output on the intel machines. We should first fix it on OSX, and currently it's annoying the intel debugging proces.