cmake HAVE_OPENGL_GL_H examples

Froser/gamemachine src/3rdparty/libtiff/CMakeLists.txt :600

check_include_file(OpenGL/gl.h HAVE_OPENGL_GL_H)

InsightSoftwareConsortium/ITK Modules/ThirdParty/TIFF/src/itktiff/cmake/OpenGLChecks.cmake :48

check_include_file(OpenGL/gl.h HAVE_OPENGL_GL_H)

Ravbug/UnityHubNative wxWidgets/src/tiff/cmake/OpenGLChecks.cmake :43

check_include_file(OpenGL/gl.h HAVE_OPENGL_GL_H)