cmake HAVE_VIDEO_OPENGL examples

FilmKilns/FilmKilns src/sdl2/cmake/sdlchecks.cmake :785 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)

inolen/redream deps/sdl2/cmake/sdlchecks.cmake :773 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)

u3d-community/U3D Source/ThirdParty/SDL/cmake/sdlchecks.cmake :882 

check_c_source_compiles ("
        #include <OpenGL/OpenGL.h>
        #include <OpenGL/CGLRenderers.h>
        int main(int argc, char** argv) { return 0; }" HAVE_VIDEO_OPENGL)

u3d-community/U3D Source/ThirdParty/SDL/cmake/sdlchecks.cmake :887 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) { return 0; }" HAVE_VIDEO_OPENGL)

google/filament third_party/libsdl2/cmake/sdlchecks.cmake :805 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)

nvMcJohn/apitest thirdparty/SDL2-2.0.1/cmake/sdlchecks.cmake :553 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)

nvMcJohn/apitest thirdparty/SDL2-2.0.1/cmake/sdlchecks.cmake :564 

endif(HAVE_VIDEO_OPENGL)

crossuo/crossuo deps/sdl-2.0.10-c1be3add38/cmake/sdlchecks.cmake :745 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)

AtomicGameEngine/AtomicGameEngine Source/ThirdParty/SDL/cmake/sdlchecks.cmake :771 

check_c_source_compiles ("
        #include <OpenGL/OpenGL.h>
        #include <OpenGL/CGLRenderers.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)

AtomicGameEngine/AtomicGameEngine Source/ThirdParty/SDL/cmake/sdlchecks.cmake :776 

check_c_source_compiles("
        #include <GL/gl.h>
        #include <GL/glx.h>
        int main(int argc, char** argv) {}" HAVE_VIDEO_OPENGL)