Re: finding png libraries in configure scripts

[Thomas Klausner <tk%giga.or.at@localhost>]

On Fri, Aug 07, 2020 at 12:48:18PM -0600, Brook Milligan wrote:
> I've been investigating the pkg-config approach, because that seemed cleanest.  However, it leads to another issue with the libpng.pc file that is installed by the png package.  That file includes "Requires: zlib", which might be reasonable because png does in fact require zlib. However, zlib might be built-in in which case no zlib.pc file is installed.  As a result, pkg-config libpng fails.
> 
> Should the libpng.pc file installed by pkgsrc be modified (i.e., include or not the Required: zlib line) depending on whether or not zlib is builtin?
> 
> What is the correct solution here?

That is already handled automatically by pkgsrc, see
devel/zlib/builtin.mk, the fake-zlib-pc target -- a fake pkg-config
file is created in such a case.

Cheers,
 Thomas