Patch DXVA AV1 support into mingw headers

scripts.d/10-mingw.sh

@@ -8,6 +8,10 @@ ffbuild_enabled() {
     return 0
 }
 
+ffbuild_dockerstage() {
+    to_df "RUN --mount=src=${SELF},dst=/stage.sh --mount=src=patches/mingw,dst=/patches run_stage /stage.sh"
+}
+
 ffbuild_dockerlayer() {
     to_df "COPY --from=${SELFLAYER} /opt/mingw/. /"
     to_df "COPY --from=${SELFLAYER} /opt/mingw/. /opt/mingw"
@@ -19,7 +23,14 @@ ffbuild_dockerfinal() {
 
 ffbuild_dockerbuild() {
     git-mini-clone "$MINGW_REPO" "$MINGW_COMMIT" mingw
-    cd mingw/mingw-w64-headers
+    cd mingw
+
+    for patch in /patches/*.patch; do
+        echo "Applying $patch"
+        git am < "$patch"
+    done
+
+    cd mingw-w64-headers
 
     unset CFLAGS
     unset CXXFLAGS