FindSDL2: Added module to locate SDL2

[jacekmigacz]

I tested it with both MinGW and MVSC.

[bradking]

Thanks for working on this. However, as discussed here:

http://www.cmake.org/Bug/view.php?id=14826#c35508

since SDL2 builds with CMake they should provide package configuration files as documented in the cmake-packages(7) manual:

http://www.cmake.org/cmake/help/v3.2/manual/cmake-packages.7.html

CMake upstream should not have to maintain builtin knowledge about every library of every package out there, especially not those that are already CMake-aware. The place to contribute support for using SDL2 from CMake-based applications is to SDL2.

[jacekmigacz]

I see. It sounds reasonable. Thanks.

[stopiccot]

But how deal with platforms where you can't install helper files to <prefix>/lib/cmake/foo-1.2/FooConfig.cmake like OS X and Windows. In real world it turns out that every project that uses SDL2 is simply maintaining their own version of FindSDL2.cmake in cmake modules dir. Taking into account that SDL2 is really widely used we can make an exception.

[bradking]

platforms where you can't install helper files to /lib/cmake/foo-1.2/FooConfig.cmake like OS X and Windows

The cmake-packages(7) manual I linked in my previous response explains that there are package registries and other ways for packages to make themselves findable. Every cross-platform project has this requirement. There is nothing special about SDL2 that CMake should need to know about it specifically. If SDL2 is unwilling to package itself for CMake in the intended way and prefers that all applications use a FindSDL2 module, then SDL2 should provide that module with their documentaiton for applications to use.

[ericoporto]

It would be really helpful if a Find SDL2 existed upstream, there's a huge proliferation of different versions of it in GitHub so it's a thing people have been looking forward to.