bug#61387: 30.0.50; Support webkit2gtk-4.1

[Ulrich Mueller <ulm@gentoo.org>]

>>>>> On Thu, 09 Feb 2023, Eli Zaretskii wrote:

> Are you proposing this for Emacs 29 or for Emacs 30?

Emacs 30, because I thought that it was to late for it to land in the
emacs-29 branch? If it could be included in Emacs 29, I would prefer
that.

>> The patch below adds a configure option --with-webkit2gtk=VALUE that
>> allows to select version 4.0 or 4.1.

> Is it really necessary to ask for a specific version?  Why cannot
> Emacs use the version that is installed?

That could be done as a fallback, but a configure switch is still
needed. Think of a package for a distro, which has to include the
information whether webkit2gtk-4.0 or 4.1 have to be pulled in as
a dependency. There, Emacs has to be built against a well-defined
version, even if both versions of webkit2 are installed on the build
system (for Gentoo, that will be the case for some transition time).

Should I update the patch to allow 3 values "4.0", "4.1", and "auto",
with "auto" being the default? And in the default case, should it
check for 4.0 or 4.1 first?