https://bugs.gentoo.org/938728
https://sourceforge.net/p/minidlna/discussion/879956/thread/81e45c3d64

With ffmpeg 7, the channels field that was previously deprecated with
ffmpeg 6 has been removed entirely, which breaks the build for this
package. This patch switches to the correct way of doing it now,
which is ch_layout.nb_channels.

diff --git a/libav.h b/libav.h
index b69752c..aed9d18 100644
--- a/libav.h
+++ b/libav.h
@@ -174,7 +174,7 @@ lav_get_interlaced(AVStream *s)
 #define lav_codec_tag(s) s->codecpar->codec_tag
 #define lav_sample_rate(s) s->codecpar->sample_rate
 #define lav_bit_rate(s) s->codecpar->bit_rate
-#define lav_channels(s) s->codecpar->channels
+#define lav_channels(s) s->codecpar->ch_layout.nb_channels
 #define lav_width(s) s->codecpar->width
 #define lav_height(s) s->codecpar->height
 #define lav_profile(s) s->codecpar->profile