Function gl::DebugMessageInsert

pub unsafe fn DebugMessageInsert(source: GLenum,
                                 type_: GLenum,
                                 id: GLuint,
                                 severity: GLenum,
                                 length: GLsizei,
                                 buf: *const GLchar)

Fallbacks: DebugMessageInsertARB, DebugMessageInsertKHR