av_free and friends are used in the ffmpeg plugin, and after r13528
ffmpeg's .pc files do not tell anymore to link needlessly to its
private library requirements.
Signed-off-by: Rémi Denis-Courmont <rem@videolan.org>

Including it after stdbool will cause compile failures as pointed by
Mike Frysinger in https://bugs.gentoo.org/show_bug.cgi?id=224289Signed-off-by: Rémi Denis-Courmont <rem@videolan.org>

Note: We may want to check that at configure time.

 in msg_Dbg.

This reverts commit 9ca4d542 which
introduces a segfault.

filter was opened). (CID 110)