bug#61988: error compiling emacs

[Eli Zaretskii]

> Cc: luangruo@yahoo.com, 61988@debbugs.gnu.org
> Date: Tue, 07 Mar 2023 17:27:59 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > From: "Ugo Tomei" <utomei@tiscali.it>
> > Cc: <luangruo@yahoo.com>,
> >     <61988@debbugs.gnu.org>
> > Date: Tue, 7 Mar 2023 15:34:26 +0100
> > 
> > Ok excuse me i try to explain better now:
> > 
> > I have installed libwebpdecoder3 and in the log I see:
> > 
> > checking for libwebpdemux >= 0.6.0... yes
> 
> That's on the screen.  I asked you to look in the file config.log,
> there should be more details there which hopefully will allow us to
> figure out what went wrong in your case.

Btw, I think I understand what's special about that system: the
libwebpdecoder library is installed if libwebp is built with the
special --enable-libwebpdecoder option.  Maybe we should detect that
separately, and adapt the Makefile to such an installation, because I
think in that case Emacs should be linked _only_ with libwebpdecoder,
not with libwebp itself.