We require threads to be supported in any case and defining this
will simplify the mutex, condition variable, etc. macros from gthread
to not always check if threads are really supported.
Fixes bug #607481.
Original commit message from CVS:
* pkgconfig/gstreamer-uninstalled.pc.in:
* pkgconfig/gstreamer.pc.in:
Remove -lgstcontrol-0.10 which never worked anyway as the lib is
called gstcontroller-0.10.
Original commit message from CVS:
Port some changes from 0.6.0/0.6.1 back to HEAD (.pc files moved to pkg-config/, .m4 file moved from plugins to core)