Werner LEMBERG wrote:
> 
> I've just been bitten by
> 
>    https://github.com/glennrp/libpng/issues/206
> 
> For this reason I suggest two improvements for the configure script of
> emacs.
> 
> (1) Use `pkg-config' before `libpng-config' to detect libpng.
> 
> (2) If `libpng-config' is used, filter out `-L/usr/lib' and
>      `-L/usr/lib64' (as suggested in issue #206).

Thanks, I installed the attached into master. It does (1), and as I understand 
it when (1) works then (2) is unnecessary. I'm hoping we don't have to do (2) as 
I worry that it might break things on some platforms.