Build FFmpeg with av1 and vp8 on macOS.

Telegram/build/prepare/prepare.py

@@ -686,6 +686,7 @@ depends:yasm/yasm
 """)
 
 stage('nv-codec-headers', """
+win:
     git clone https://github.com/FFmpeg/nv-codec-headers.git
     cd nv-codec-headers
     git checkout n11.1.5.1
@@ -735,6 +736,7 @@ depends:yasm/yasm
     --enable-decoder=aasc \
     --enable-decoder=alac \
     --enable-decoder=alac_at \
+    --enable-decoder=av1 \
     --enable-decoder=flac \
     --enable-decoder=gif \
     --enable-decoder=h264 \
@@ -787,6 +789,7 @@ depends:yasm/yasm
     --enable-decoder=pcm_u32le \
     --enable-decoder=pcm_u8 \
     --enable-decoder=vorbis \
+    --enable-decoder=vp8 \
     --enable-decoder=wavpack \
     --enable-decoder=wmalossless \
     --enable-decoder=wmapro \