revert changes to building libs under windows

.github/workflows/generate-libs.yml

@@ -44,17 +44,6 @@ jobs:
       if: matrix.os == 'ubuntu-latest'
       run: sudo apt-get update && sudo apt-get install -y libx11-dev libxext-dev libxft-dev libxinerama-dev libxcursor-dev libxrender-dev libxfixes-dev libgl1-mesa-dev libglu1-mesa-dev
 
-    - name: Install MSYS2
-      if: matrix.os == 'windows-latest'
-      uses: msys2/setup-msys2@v2
-      with:
-        update: true
-        msystem: ucrt64
-        pacboy: >-
-          toolchain:p
-          cmake:p
-          ninja:p
-
     - name: Check out code
       uses: actions/checkout@v4
 

fltk-build.bat

@@ -50,7 +50,7 @@ IF %ERRORLEVEL% NEQ 0 EXIT /B 1
 
 CD ..
 
-cmake -G Ninja -S fltk -B build -DFLTK_BUILD_TEST=OFF -DCMAKE_BUILD_TYPE=Release -DFLTK_BUILD_EXAMPLES=OFF -DFLTK_BUILD_FLUID=OFF -DFLTK_BUILD_FLTK_OPTIONS=OFF -DOPTION_USE_SYSTEM_LIBJPEG=OFF -DOPTION_USE_SYSTEM_LIBPNG=OFF -DOPTION_USE_SYSTEM_ZLIB=OFF -DCMAKE_INSTALL_PREFIX=%CMAKE_INSTALL_PREFIX% -DCMAKE_INSTALL_INCLUDEDIR=%CMAKE_INSTALL_INCLUDEDIR% -DFLTK_INCLUDEDIR=%CMAKE_INSTALL_PREFIX%/%CMAKE_INSTALL_INCLUDEDIR% -DCMAKE_INSTALL_LIBDIR=%CMAKE_INSTALL_LIBDIR% -DFLTK_LIBDIR=%CMAKE_INSTALL_PREFIX%/%CMAKE_INSTALL_LIBDIR%
+cmake -G "MinGW Makefiles" -S fltk -B build -DFLTK_BUILD_TEST=OFF -DCMAKE_BUILD_TYPE=Release -DFLTK_BUILD_EXAMPLES=OFF -DFLTK_BUILD_FLUID=OFF -DFLTK_BUILD_FLTK_OPTIONS=OFF -DOPTION_USE_SYSTEM_LIBJPEG=OFF -DOPTION_USE_SYSTEM_LIBPNG=OFF -DOPTION_USE_SYSTEM_ZLIB=OFF -DCMAKE_INSTALL_PREFIX=%CMAKE_INSTALL_PREFIX% -DCMAKE_INSTALL_INCLUDEDIR=%CMAKE_INSTALL_INCLUDEDIR% -DFLTK_INCLUDEDIR=%CMAKE_INSTALL_PREFIX%/%CMAKE_INSTALL_INCLUDEDIR% -DCMAKE_INSTALL_LIBDIR=%CMAKE_INSTALL_LIBDIR% -DFLTK_LIBDIR=%CMAKE_INSTALL_PREFIX%/%CMAKE_INSTALL_LIBDIR%
 IF %ERRORLEVEL% NEQ 0 EXIT /B 1
 cmake --build build --parallel
 IF %ERRORLEVEL% NEQ 0 EXIT /B 1