XQuartz.app needs to be able to find the `startx' from the `xinit'
package, but it defaults to assuming it is in the same directory as
the Xquartz binary, which it will never be. This restores a patch that
uses environment variables to locate `startx', which is what the
`xquartz' package is expecting to use.
Things done:
- use libGLU instead of mesa for darwin support
- move patches from local to github url
- fixup xquartz install
There may still be some issues at runtime. PRs welcome!
Fixes#40196