build: add alternative PKG_CONFIG_PATH

This is a cryptographically signed message in MIME format.

udev Makefile.am has two different .pc files and put them
into two locations. Don't know if changing the udev Makefile
or changing the pkgconfig paths is the right way - someone
has to decide :)

udev and vala use an additional pkg-config dir
add it to the path

discovered because openobex did not find udev.pc

Signed-off-by: Dirk Neukirchen <dirkneukirchen@web.de>

SVN-Revision: 39792