Adds the ability to pass a WINDOWING_LIB variable to 'make' which sets `--with-sdl` or `--with-glfw` (#2138)
Adds the ability to pass a WINDOWING_LIB variable to 'make' which sets `--with-sdl` or `--with-glfw` (#2138)

* Adds the ability to pass a WINDOWING_LIB variable to 'make' which sets --with-sdl or --with-glfw

* Adds the ability to pass extra GENie args to 'make'
emoon/bgfx,bkaradzic/bgfx,LWJGL-CI/bgfx,jpcy/bgfx,LWJGL-CI/bgfx,mendsley/bgfx,emoon/bgfx,LWJGL-CI/bgfx,jpcy/bgfx,bkaradzic/bgfx,bkaradzic/bgfx,LWJGL-CI/bgfx,jpcy/bgfx,jdryg/bgfx,jdryg/bgfx,bkaradzic/bgfx,jdryg/bgfx,mendsley/bgfx,emoon/bgfx,jdryg/bgfx,jpcy/bgfx,mendsley/bgfx