QGLContext::bindTexture does not generates mipmaps

QGLContext::bindTexture (if calling with QGLContext::MipmapBindOption) does not generates mipmaps due to it checks
qgl_extensions()->hasOpenGLExtension(QOpenGLExtensions::GenerateMipmap)
which always returns false.

Because it calls qt_gl_resolve_extensions() where checks some extensions and there is no checking for "GL_SGIS_generate_mipmap" extension and therefore bit flag set for QOpenGLExtensions::GenerateMipmap