meson: add Avisynth option, compile libass_gdi_fontselect

Sadly, building with Avisynth is still broken.

meson.build

@@ -192,6 +192,10 @@ foreach dep: [
     endif
 endforeach
 
+if host_machine.system() == 'windows' and get_option('avisynth').enabled()
+    conf.set('WITH_AVISYNTH', 1) # bundled separately with installer
+endif
+
 if host_machine.system() == 'windows' and not get_option('directsound').disabled()
     dsound_dep = cc.find_library('dsound', required: get_option('directsound'))
     winmm_dep = cc.find_library('winmm', required: get_option('directsound'))

meson_options.txt

@@ -6,6 +6,7 @@ option('directsound', type: 'feature', description: 'DirectSound audio output')
 option('default_audio_output', type: 'combo', choices: ['auto', 'ALSA', 'OpenAL', 'PulseAudio', 'PortAudio', 'DirectSound'], description: 'Default audio output')
 
 option('ffms2', type: 'feature', description: 'FFMS2 video source')
+option('avisynth', type: 'feature', description: 'AviSynth video source')
 
 option('fftw3', type: 'feature', description: 'FFTW3 support')
 option('hunspell', type: 'feature', description: 'Hunspell spell checker')

src/meson.build

@@ -33,7 +33,6 @@ aegisub_src = files(
     'auto4_lua_assfile.cpp',
     'auto4_lua_dialog.cpp',
     'auto4_lua_progresssink.cpp',
-    'avisynth_wrap.cpp',
     'base_grid.cpp',
     'charset_detect.cpp',
     'colorspace.cpp',
@@ -173,8 +172,12 @@ if host_machine.system() == 'darwin'
     ]
 elif host_machine.system() == 'windows'
     aegisub_src += [
-        'font_file_lister_gdi.cpp'
+        'avisynth_wrap.cpp',
+        'font_file_lister_gdi.cpp',
+        'libass_gdi_fontselect.cpp',
+        'video_provider_avs.cpp',
     ]
+
     if cc.has_header('wingdi.h')
         deps += cc.find_library('gdi32', required: true)
     else