meson: add fixed-point Vorbis (Tremor) decoder support

meson_options.txt

@@ -128,6 +128,7 @@ option('mpg123', type: 'feature', description: 'MP3 decoder using libmpg123')
 option('opus', type: 'feature', description: 'Opus decoder plugin')
 option('sidplay', type: 'feature', description: 'C64 SID support via libsidplayfp or libsidplay2')
 option('sndfile', type: 'feature', description: 'libsndfile decoder plugin')
+option('tremor', type: 'feature', description: 'Fixed-point vorbis decoder plugin')
 option('vorbis', type: 'feature', description: 'Vorbis decoder plugin')
 option('wavpack', type: 'feature', description: 'WavPack decoder plugin')
 option('wildmidi', type: 'feature', description: 'WildMidi decoder plugin')

src/decoder/plugins/meson.build

@@ -36,8 +36,9 @@ if flac_dep.found()
   ]
 endif
 
-conf.set('ENABLE_VORBIS_DECODER', libvorbis_dep.found())
-if libvorbis_dep.found()
+conf.set('ENABLE_VORBIS_DECODER', libvorbis_dep.found() or libvorbisidec_dep.found())
+conf.set('HAVE_TREMOR', libvorbisidec_dep.found())
+if libvorbis_dep.found() or libvorbisidec_dep.found()
   decoder_plugins_sources += [
     'VorbisDecoderPlugin.cxx',
     'VorbisDomain.cxx',
@@ -181,6 +182,7 @@ decoder_plugins = static_library(
     libsidplay_dep,
     libsndfile_dep,
     libvorbis_dep,
+    libvorbisidec_dep,
     ogg_dep,
     wavpack_dep,
     wildmidi_dep,

src/lib/xiph/meson.build

 libflac_dep = dependency('flac', version: '>= 1.2', required: get_option('flac'))
 libopus_dep = dependency('opus', required: get_option('opus'))
 libvorbis_dep = dependency('vorbis', required: get_option('vorbis'))
+libvorbisidec_dep = dependency('vorbisidec', required: get_option('tremor'))
+
+if get_option('vorbis').enabled() and get_option('tremor').enabled()
+	error('Cannot build both, the Vorbis decoder AND the Tremor (Vorbis fixed-point) decoder')
+endif
 
 libvorbisenc_dep = dependency('', required: false)
 if need_encoder and not get_option('vorbisenc').disabled()
@@ -13,7 +18,7 @@ if need_encoder and not get_option('vorbisenc').disabled()
   endif
 endif
 
-if libopus_dep.found() or libvorbis_dep.found() or libvorbisenc_dep.found()
+if libopus_dep.found() or libvorbis_dep.found() or libvorbisenc_dep.found() or libvorbisidec_dep.found()
   libogg_dep = dependency('ogg')
 else
   libogg_dep = dependency('', required: false)