CMake scripts and patches to build dav1d, libass and other projects used in FFmpeg build script avbuild and other projects

Build steps can be found in github actions. harfbuzz hb-ft.h is required by FFmpeg, more steps are required. Prebuilt binaries can be found in ci artifacts: static libs w/o LTO and LTO enabled shared libs

libmdk-dep/dep.7z contains runtime (dynamic) binaries and libs I used to build libmdk. libmdk-dep/dep-av.7z contains some libs used by avbuild

generate c headers for fribidi first(if not exists)

cmake -DFRIBIDI_GENTAB=1 -Bbuild -DCMAKE_BUILD_TYPE=${{ matrix.config }}
cmake --build build -t gen_tab

dav1d and libass requires clang installed by visual studio. clang-cl is used to build arm64 asm