[poppler] (2/2) build: have libpng detection use libpng

[Albert Astals Cid]

A Dissabte, 13 de març de 2010, Jan Engelhardt va escriure:
> parent 3f0ab18596ab9c2a9fa03293a91da527bdc9ea31 ()
> commit 60d6c3cba49a7530319070bc7e75a5bddd893bd0
> Author: Jan Engelhardt <jengelh at medozas.de>
> Date:   Sat Mar 13 12:34:09 2010 +0100
> 
> build: have libpng detection use libpng
> ---

libpng was already switched to pkg-config in 
http://cgit.freedesktop.org/poppler/poppler/commit/?id=f9425c0b5b112ac673d0499f79a743afce719593

Albert