crosscompiling using mingw

export CC=i686-w64-mingw32-gcc
export CXX=i686-w64-mingw32-g++
export RC=i686-w64-mingw32-windres

./bootstrap-vcpkg.sh -disableMetrics -useSystemBinaries
./vcpkg install opengl:x86-mingw glew:x86-mingw freetype:x86-mingw eigen3:x86-mingw fmt:x86-mingw libpng:x86-mingw libjpeg-turbo:x86-mingw lua:x86-mingw

edit $vcpkg/installed/x86-mingw/share/glew/glew-targets-{release,debug}.cmake

lib/glew32.a -> lib/libglew32.a,lib/glew32d.a -> lib/libglew32d.a

cmake -S$PWD -B/tmp/mingw -G Ninja -DCMAKE_BUILD_TYPE=Release -DENABLE_SPICE=OFF -DENABLE_TTF=ON -DENABLE_QT=OFF -DENABLE_WIN=ON -DENABLE_NLS=OFF -DCMAKE_SYSTEM_NAME=Windows -DVCPKG_TARGET_TRIPLET=x86-mingw -DCMAKE_FIND_USE_CMAKE_SYSTEM_PATH=OFF -DCMAKE_TOOLCHAIN_FILE=$vcpkg/scripts/buildsystems/vcpkg.cmake