enabling MSYS2 build

[vasilich-tregub]

In a fork (see https://github.com/vasilich-tregub/SVT-JPEG-XS), have corrected ifdef conditionals in x64inc.asm and nasm-related sections of the root CMakeLists.txt. Also, added checks for MSYS in CMakeLists' conditionals. With these changes, the forked repo can be readily used to build SVT-JPEG-XS in MSYS2: I've added instructions to READMEs. MSYS build is convenient: for the Windows platform, the parent repo's README recommends building FFMPEG with MSYS.

Still, there remain many lines (should we address if(UNIX) conditionals in subproject CMakeLists files, for example) begging for update, and not just in CMakeLists files. With what has been done so far, is it enough to ask for pull request?

Build/windows/build.bat clean runs build release immediately after clean. Is it by design or should we separate the two operations?

[tszumski]

Hi @vasilich-tregub, thank you for your comments.

1. Could you provide justification what are the benefits of using MSYS over current approach ?
2. Could you also check if your changes does not break current windows/linux approach ?

Still, there remain many lines (should we address if(UNIX) conditionals in subproject CMakeLists files, for example) begging for update, and not just in CMakeLists files. With what has been done so far, is it enough to ask for pull request?

Answer: I would suggest preparing all changes in one PR

Build/windows/build.bat clean runs build release immediately after clean. Is it by design or should we separate the two operations?

Answer: It is by design

[vasilich-tregub]

Hi @tszumski,

don't understand what you mean what are the benefits of using MSYS over current approach. Your repo already tries to use the MSYS2 build system, as ffmpeg-plugin/readme.md in your repo reads,

Windows ffmpeg plugin
1. Download and install binary/installer from: https://www.msys2.org/
2. Open terminal MINGW64
...
b) Install packages:
pacman -S make mingw-w64-x86_64-gcc mingw-w64-x86_64-cmake mingw-w64-x86_64-yasm mingw-w64-x86_64-diffutils
...
4. Create installation directory and export env variable:
mkdir install-dir
export INSTALL_DIR=$PWD/install-dir
5. Compile and install svt-jpeg-xs libs(In main svt-jpegxs folder)
a) Configure:
cmake -S . -B svtjpegxs-build -DBUILD_APPS=off -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DCMAKE_INSTALL_PREFIX=$INSTALL_DIR

but, unfortunately, the Configure operation
cmake -S . -B svtjpegxs-build -DBUILD_APPS=off -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF \
-DCMAKE_INSTALL_PREFIX=$INSTALL_DIR
does not succeed as the conditionals of the root CMakeLists.txt of your repo (https://github.com/OpenVisualCloud/SVT-JPEG-XS/blob/main/CMakeLists.txt) fail to correctly identify the environment. You can compare your CMakeLists.txt and CmakeLists.txt of my fork (https://github.com/vasilich-tregub/SVT-JPEG-XS/blob/main/CMakeLists.txt) to see my edits. You can browse commits to see the other file edits in my fork.

My corrections do not change the lines governing the operations under MSVC and Linux toolchains, if this is what you care about when talking about 'current windows/linux approach'. I verified that the MSVC and Linux builds with my fork are identical with the parent repo builds. Corrections only make the parent repo to be suitable for building ffmpeg plugin for Windows platform, because this plugin requires SVT-JPEG-XS to be built under MSYS2 (MinGW) for this purpose.