I don't know what you want to get, so in general:
Build steps:
1. Download the old installer:
https://repo.msys2.org/distrib/x86_64/msys2-x86_64-20211130.exe 30-Nov-2021 19:34 98M
2. Follow the 2-7 steps described on this page
https://www.msys2.org/3. You run the console: mingw64.exe
4. You supplement the msys2 libraries with:
pacman --noconfirm -S base-devel mingw-w64-x86_64-toolchain mingw-w64-x86_64-meson mingw-w64-x86_64-gegl
pacman -S mingw-w64-x86_64-gimp mingw-w64-x86_64-cmake
If there is no dependency, you will find them here:
https://packages.msys2.org/search5. You copy the source files to c:\msys64\home\Your name
6. In the console you go inside the source (where the meson.build file is), e.g.:
cd GEGL_highpass_of_mean_curvature-main/GEGL_highpass_of_mean_curvature-main
(path must be without spaces and with backslashes, i.e. /)
7. Paste code:
meson setup --buildtype=release build
ninja -C build
8. Look for the dll file in the 'build' directory.