Re: finding png libraries in configure scripts

[Brook Milligan <brook%nmsu.edu@localhost>]

> On Aug 7, 2020, at 1:37 PM, Thomas Klausner <tk%giga.or.at@localhost> wrote:
> 
> **Warning: This email originated external to the NMSU email system. Do not click on links or open attachments unless you are sure the content is safe.
> 
> 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.

OK, but how is that run?  On my system there is no lib/pkgconfig/zlib.pc file installed.

Cheers,
Brook