cmake HAVE_GL_GL_H examples

Froser/gamemachine src/3rdparty/libtiff/CMakeLists.txt :596 

check_include_file(GL/gl.h HAVE_GL_GL_H)

InsightSoftwareConsortium/ITK Modules/ThirdParty/TIFF/src/itktiff/cmake/OpenGLChecks.cmake :44 

check_include_file(GL/gl.h HAVE_GL_GL_H)

FreeCAD/FreeCAD cMake/ConfigureChecks.cmake :12 

check_include_file(GL/gl.h HAVE_GL_GL_H)

Ravbug/UnityHubNative wxWidgets/src/tiff/cmake/OpenGLChecks.cmake :39 

check_include_file(GL/gl.h HAVE_GL_GL_H)