Sets whether the #GdkGLContext should be forward compatible.
Forward compatibile contexts must not support OpenGL functionality that
has been marked as deprecated in the requested version; non-forward
compatible contexts, on the other hand, must support both deprecated and
non deprecated functionality.
The #GdkGLContext must not be realized or made current prior to calling
this function.
Sets whether the #GdkGLContext should be forward compatible.
Forward compatibile contexts must not support OpenGL functionality that has been marked as deprecated in the requested version; non-forward compatible contexts, on the other hand, must support both deprecated and non deprecated functionality.
The #GdkGLContext must not be realized or made current prior to calling this function.