bug#56434: 29.0.50; PGTK cannot yank after second frame is deleted

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Protesilaos Stavrou <info@protesilaos.com> writes:

> Dear maintainers,
>
> I can reproduce the following on emacs -Q:
>
> 1. Produce a second frame with either M-x tear-off-window or C-x 5 b BUFFER
>
> 2. Mark a region with some text and type M-w
>
> 3. Delete the frame either via the system's window manager or C-x 5 0
>
> 4. Type C-y
>
> 5. Emacs hangs and displays the echo area message "Waiting for reply from
>    selection owner..."
>
> Setting debug-on-error to non-nil has no effect.  When Emacs hangs, the
> shell prints this:
>
>     (emacs:2090): GLib-GObject-CRITICAL **: 14:53:23.604: g_object_ref: assertion 'G_IS_OBJECT (object)' failed

Should be fixed now, please test.

> In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.34, cairo version 1.17.6)
>  of 2022-07-06 built on kronos
> Repository revision: f65e4c46a3418c7f24f53503feda42e844951997
> Repository branch: master
> System Description: Arch Linux
>
> Configured using:
>  'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
>  --localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games
>  --with-modules --without-libotf --without-m17n-flt --without-gconf
>  --with-native-compilation --with-xinput2 --with-pgtk --without-xaw3d
>  --with-sound=no --without-gpm --without-compress-install
>  '--program-transform-name=s/\([ec]tags\)/\1.emacs/'
>  'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions
>  -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security
>  -fstack-clash-protection -fcf-protection'
>  LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Your configure options are mostly redundant.  `--with-xinput2' and
`--without-xaw3d' have no effect on PGTK, and `--with-modules' has been
the default for a long time.

These redundant configure flags make reading generated bug reports
confusing.  Please report the problem to the packager.

Thanks.