bug#65042: 30.0.50; alpha-background doesn't effect background of stipple in emacs 30.0.50 pgtk

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: 65042@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>
> Date: Fri, 04 Aug 2023 21:28:50 +0800
> 
> Felix <felix.dick@web.de> writes:
> 
> > This time it works,
> > Thanks for this, and thanks your work on Emacs in general!
> 
> OK, thanks.  Eli, should this reach Emacs 29.2, or is it too involved
> for the release branch?

This is okay for the release branch, thanks.