meson: make libplacebo a required dependency

Make it not possible to build mpv without the latest libplacebo anymore.
This will allow for less code duplication between mpv and libplacebo,
and in the future also let us delete legacy ifdefs and track libplacebo
better.

meson.build

@@ -23,6 +23,9 @@ libavutil = dependency('libavutil', version: '>= 56.70.100')
 libswresample = dependency('libswresample', version: '>= 3.9.100')
 libswscale = dependency('libswscale', version: '>= 5.9.100')
 
+libplacebo = dependency('libplacebo', version: '>=6.338.0', fallback: ['libplacebo', 'libplacebo'],
+    default_options: ['default_library=static', 'demos=false'])
+
 libass = dependency('libass', version: '>= 0.12.2')
 
 # the dependency order of libass -> ffmpeg is necessary due to
@@ -32,6 +35,7 @@ dependencies = [libass,
                 libavfilter,
                 libavformat,
                 libavutil,
+                libplacebo,
                 libswresample,
                 libswscale]
 
@@ -44,6 +48,7 @@ features = {
     'avif-muxer': libavformat.version().version_compare('>= 59.24.100'),
     'libass': true,
     'threads': true,
+    'libplacebo': true,
 }
 
 
@@ -234,6 +239,12 @@ sources = files(
     'video/repack.c',
     'video/sws_utils.c',
 
+    ## libplacebo
+    'video/out/placebo/ra_pl.c',
+    'video/out/placebo/utils.c',
+    'video/out/vo_gpu_next.c',
+    'video/out/gpu_next/context.c',
+
     ## osdep
     'osdep/io.c',
     'osdep/semaphore_osx.c',
@@ -930,16 +941,6 @@ if features['jpeg']
     dependencies += jpeg
 endif
 
-libplacebo = dependency('libplacebo', version: '>=6.292.0', required: get_option('libplacebo'))
-features += {'libplacebo': libplacebo.found()}
-if features['libplacebo']
-    dependencies += libplacebo
-    sources += files('video/out/placebo/ra_pl.c',
-                     'video/out/placebo/utils.c',
-                     'video/out/vo_gpu_next.c',
-                     'video/out/gpu_next/context.c')
-endif
-
 sdl2_video = get_option('sdl2-video').require(
     features['sdl2'],
     error_message: 'sdl2 was not found!',
@@ -1257,7 +1258,7 @@ endif
 # vulkan
 vulkan_opt = get_option('vulkan').require(
     libplacebo.get_variable('pl_has_vulkan', default_value: '0') == '1',
-    error_message: 'libplacebo could not be found!',
+    error_message: 'libplacebo compiled without vulkan support!',
 )
 vulkan = dependency('vulkan', version: '>= 1.1.70', required: vulkan_opt)
 features += {'vulkan': vulkan.found()}
@@ -1330,9 +1331,8 @@ endif
 
 vulkan_interop = get_option('vulkan-interop').require(
     features['vulkan'] and vulkan.version().version_compare('>=1.3.238') and
-    features['libplacebo'] and
     libavutil.version().version_compare('>=58.11.100'),
-    error_message: 'Vulkan Interop requires vulkan headers >= 1.3.238, libplacebo, and libavutil >= 58.11.100',
+    error_message: 'Vulkan Interop requires vulkan headers >= 1.3.238, and libavutil >= 58.11.100',
 )
 features += {'vulkan-interop': vulkan_interop.allowed()}
 if vulkan_interop.allowed()
@@ -1426,14 +1426,9 @@ features += {'vaapi': vaapi.allowed()}
 if features['vaapi']
     dependencies += libva
     sources += files('video/filter/vf_vavpp.c',
-                     'video/vaapi.c')
-endif
-
-features += {'vaapi-egl': features['vaapi'] and features['egl'] and features['drm']}
-features += {'vaapi-libplacebo': features['vaapi'] and libplacebo.found()}
-
-if features['vaapi-egl'] or features['vaapi-libplacebo']
-    sources += files('video/out/hwdec/hwdec_vaapi.c')
+                     'video/vaapi.c',
+                     'video/out/hwdec/hwdec_vaapi.c',
+                     'video/out/hwdec/dmabuf_interop_pl.c')
 endif
 
 dmabuf_interop_gl = features['egl'] and features['drm']
@@ -1442,12 +1437,6 @@ if features['dmabuf-interop-gl']
     sources += files('video/out/hwdec/dmabuf_interop_gl.c')
 endif
 
-dmabuf_interop_pl = features['vaapi-libplacebo']
-features += {'dmabuf-interop-pl': dmabuf_interop_pl}
-if features['dmabuf-interop-pl']
-    sources += files('video/out/hwdec/dmabuf_interop_pl.c')
-endif
-
 vdpau_opt = get_option('vdpau').require(
     features['x11'],
     error_message: 'x11 was not found!',
@@ -1786,7 +1775,6 @@ if get_option('tests')
 endif
 
 summary({'d3d11': features['d3d11'],
-         'gpu-next': features['libplacebo'],
          'javascript': features['javascript'],
          'libmpv': get_option('libmpv'),
          'lua': features['lua'],