--enable-foo will search for the foo.pc and die if not provided
--disable-foo will not search anything related to foo
'' will search for foo.pc and give a message if foo.pc is not provided.

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

...rather than extension (if any). Fixes: #3016.
Also make the code a bit more generic.

Rewrite quartztext to use CoreText API instead of ATSUI. ATSUI only works in 32bit applications, but CoreText requires Mac OS X 10.5 or later. This change makes this module unusable on older versions of Mac OS X.
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

This reverts commit 224e96f2.

This reverts commit d0905507.

This reverts commit 7b4a81eb.

This reverts commit aeb379ed.

This reverts commit 98691bc7.

in order to be consistent with other libvlc methods (libvlc_media_player_get_length, get_time, ...)