Make ConTeXt optional libraries

Get the repository and submodules

Clone with

git clone --recursive

or after cloning run:

git submodule update --init

Build the libraries

For native platform:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j10
ls build/*.so # or other

Cross-compiling from Linux to Windows with mingw:

cmake -S . -B build-w64 --toolchain cmake/mingw-64.cmake -DCMAKE_BUILD_TYPE=Release
cmake --build build-w64 -j10
ls build-w64/*.dll