ci/mingw: add dav1d decoder

ffmpeg has built-in decoders for almost all common formats, except AV1.
dav1d allows the CI build to play AV1 videos without a hwdec-capable GPU.

ci/build-mingw64.sh

@@ -121,6 +121,16 @@ _zlib () {
 }
 _zlib_mark=lib/libz.dll.a
 
+_dav1d () {
+    [ -d dav1d ] || $gitclone https://code.videolan.org/videolan/dav1d.git
+    builddir dav1d
+    meson setup .. --cross-file "$prefix_dir/crossfile" \
+        -Denable_{tools,tests}=false
+    makeplusinstall
+    popd
+}
+_dav1d_mark=lib/libdav1d.dll.a
+
 _ffmpeg () {
     [ -d ffmpeg ] || $gitclone https://github.com/FFmpeg/FFmpeg.git ffmpeg
     builddir ffmpeg
@@ -129,7 +139,7 @@ _ffmpeg () {
         --enable-cross-compile --cross-prefix=$TARGET- --arch=${TARGET%%-*}
         --cc="$CC" --cxx="$CXX" $commonflags
         --disable-{doc,programs,muxers,encoders}
-        --enable-encoder=mjpeg,png
+        --enable-encoder=mjpeg,png --enable-libdav1d
     )
     pkg-config vulkan && args+=(--enable-vulkan --enable-libshaderc)
     ../configure "${args[@]}"
@@ -254,7 +264,7 @@ _luajit () {
 }
 _luajit_mark=lib/libluajit-5.1.a
 
-for x in iconv zlib shaderc spirv-cross nv-headers; do
+for x in iconv zlib shaderc spirv-cross nv-headers dav1d; do
     build_if_missing $x
 done
 if [[ "$TARGET" != "i686-"* ]]; then
@@ -299,7 +309,7 @@ if [ "$2" = pack ]; then
     dlls=(
         libgcc_*.dll lib{ssp,stdc++,winpthread}-[0-9]*.dll # compiler runtime
         av*.dll sw*.dll lib{ass,freetype,fribidi,harfbuzz,iconv,placebo}-[0-9]*.dll
-        lib{shaderc_shared,spirv-cross-c-shared}.dll zlib1.dll
+        lib{shaderc_shared,spirv-cross-c-shared,dav1d}.dll zlib1.dll
         # note: vulkan-1.dll is not here since drivers provide it
     )
     mv -v "${dlls[@]}" ..