undefined reference to `ff_ac3_find_syncword' when ac3 parser is disabled, aac enabled

[Adam Baxter]

Summary of the bug: enabling aac only results in undefined reference to `ff_ac3_find_syncword'
How to reproduce:

./configure --disable-everything --enable-ffmpeg --enable-ffprobe --disable-stripping --enable-static --disable-shared --enable-pic --extra-ldexeflags=-static --prefix=/output/ --enable-cross-compile --cross-prefix=x86_64-linux-musl- --arch=x86_64 --prefix=/output --target-os=linux --enable-demuxer=mpegts --enable-decoder=aac --enable-parser=aac --enable-demuxer=aac

make

...
#25 10.88 LD    ffmpeg_g
#25 10.88 LD    ffprobe_g
#25 11.09 /usr/bin/../lib/gcc/x86_64-linux-musl/13.1.0/../../../../x86_64-linux-musl/bin/ld: libavcodec/libavcodec.a(aac_ac3_parser.o): in function `ff_aac_ac3_parse':
#25 11.09 /src/ffmpeg-6.0/libavcodec/aac_ac3_parser.c:99: undefined reference to `ff_ac3_find_syncword'
#25 11.09 /usr/bin/../lib/gcc/x86_64-linux-musl/13.1.0/../../../../x86_64-linux-musl/bin/ld: libavcodec/libavcodec.a(aac_ac3_parser.o): in function `ff_aac_ac3_parse':
#25 11.09 /src/ffmpeg-6.0/libavcodec/aac_ac3_parser.c:99: undefined reference to `ff_ac3_find_syncword'
#25 11.24 collect2: error: ld returned 1 exit status
#25 11.24 make: *** [Makefile:131: ffprobe_g] Error 1
#25 11.24 make: *** Waiting for unfinished jobs....
#25 11.24 collect2: error: ld returned 1 exit status
#25 11.24 make: *** [Makefile:131: ffmpeg_g] Error 1

Same issue with the 6.0 tarball and git 16fdb48e0dead244bddf3a0ae9d459d02b4443b1

adding --enable-parser=ac3 works around this issue, but it seems like these two components should be independent.

[James]

Should be fixed in 35af1695a9ad6f950e03efd156b99898b94dd57c.