Using pkg-config in qmake
I saw some random mentions of pkg-config support in qmake lying around on the ‘net, but of course found no documentation about it in Qt. (I even mailed their support dept. which said it did not exist :) ).
Nevertheless it does (at least in Qt 4.3.3). So for example to add the necessary magic to use Alsa, just do this:
CONFIG += link_pkgconfig PKGCONFIG += alsa