MinGW+MSYS2: Cmake 'install' action doesn't actually install anything useful

[HolyBlackCat]

I'm using Bullet for the first time.

Tried the standard CMake build sequence: cmake, make, then make install (the exact commands are at the bottom).

What I expected: make install should've copied at least libraries and headers into $CMAKE_INSTALL_PREFIX/lib and $CMAKE_INSTALL_PREFIX/include respectively, plus any additional files (.cmake, etc). Every other library I've used before follows this convention.

What actually happened: the only files that were installed are two .cmake files (BulletConfig.cmake and UseBullet.cmake) into $CMAKE_INSTALL_PREFIX/lib/cmake/bullet. And nothing else.

---

I'm on Windows, but am using MinGW with MSYS2. From the point of view of a build system, it should act almost exactly like a linux environment.

I've used following commands:

cd "/z/Projects/C++/depb/tmp/bullet3-2.89"
mkdir -p _build
cd _build
cmake -Wno-dev \
  -DCMAKE_C_COMPILER="clang" -DCMAKE_CXX_COMPILER="clang++" -DCMAKE_C_FLAGS="-femulated-tls --target=x86_64-w64-windows-gnu" -DCMAKE_CXX_FLAGS="-femulated-tls --target=x86_64-w64-windows-gnu" -DCMAKE_EXE_LINKER_FLAGS="-pthread -femulated-tls --target=x86_64-w64-windows-gnu" -DCMAKE_MODULE_LINKER_FLAGS="-pthread -femulated-tls --target=x86_64-w64-windows-gnu" -DCMAKE_SHARED_LINKER_FLAGS="-pthread -femulated-tls --target=x86_64-w64-windows-gnu" \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX="/z/Projects/C++/depb/output" -DCMAKE_SYSTEM_PREFIX_PATH=/z/Projects/C++/depb/output \
  -DBUILD_BULLET2_DEMOS:BOOL=OFF -DBUILD_EXTRAS:BOOL=OFF -DBUILD_OPENGL3_DEMOS:BOOL=OFF \
  -DBUILD_UNIT_TESTS:BOOL=OFF -DBUILD_CLSOCKET:BOOL=OFF -DBUILD_CPU_DEMOS:BOOL=OFF -DBUILD_ENET:BOOL=OFF \
  -G "MSYS Makefiles" .. 
make -j4
make install

[HolyBlackCat]

Found the culprit: CMakeLists.txt:425:

IF("${CMAKE_GENERATOR}" MATCHES "Unix Makefiles")
	OPTION(INSTALL_LIBS "Set when you want to install libraries" ON)
ELSE()
	IF(APPLE AND FRAMEWORK)
		OPTION(INSTALL_LIBS "Set when you want to install libraries" ON)
	ELSE()
#by default, don't enable the 'INSTALL' option for Xcode and MSVC projectfiles
		OPTION(INSTALL_LIBS "Set when you want to install libraries" OFF)
	ENDIF()
ENDIF()

-DINSTALL_LIBS:BOOL=ON overrides this and solves the issue.

I think I see the intent behind this: "install libraries only if not using an IDE", but I'm not sure what the proper solution would be.

Simply adding "MSYS Makefiles" and "MinGW Makefiles" would work, but it's not optimal, as there are many more makefile flavors that could be used.