Обсуждение: BUG #15306: Use pkg-config for searching libxml2 header

The following bug has been logged on the website:

Bug reference:      15306
Logged by:          Ding Xiang Fei
Email address:      dingxiangfei2009@gmail.com
PostgreSQL version: 11beta2
Operating system:   NixOS
Description:

This is an improvement suggestion. In the configure script,

https://github.com/postgres/postgres/blob/master/configure.in#L896

this part uses `xml2-config` program to find the `libxml2` headers.

It would be more appropriate to use pkg-config program to search `libxml2`
headers.

=?utf-8?q?PG_Bug_reporting_form?= <noreply@postgresql.org> writes:
> This is an improvement suggestion. In the configure script,
> https://github.com/postgres/postgres/blob/master/configure.in#L896
> this part uses `xml2-config` program to find the `libxml2` headers.

Right ...

> It would be more appropriate to use pkg-config program to search `libxml2`
> headers.

Why?  Under what circumstances would xml2-config not be present
(assuming that libxml2 is) or give a less desirable answer than
pkg-config?  What would you have us do on platforms lacking pkg-config?

            regards, tom lane

2018-07-31 20:33 keltezéssel, Tom Lane írta:
> =?utf-8?q?PG_Bug_reporting_form?= <noreply@postgresql.org> writes:
>> This is an improvement suggestion. In the configure script,
>> https://github.com/postgres/postgres/blob/master/configure.in#L896
>> this part uses `xml2-config` program to find the `libxml2` headers.
> 
> Right ...
> 
>> It would be more appropriate to use pkg-config program to search `libxml2`
>> headers.
> 
> Why?  Under what circumstances would xml2-config not be present
> (assuming that libxml2 is) or give a less desirable answer than
> pkg-config?

The Yocto cross-compiler framework (since Yocto 2.2 IIRC) does not
allow the "binconfig" scripts for XML2 and GD and for some other
libraries.

The pkg-config scripts are not just preferred but mandatory.

>  What would you have us do on platforms lacking pkg-config?

That should be kept as a fallback in PKG_CHECK_MODULES().

Best regards,
Zoltán Böszörményi

> 
>             regards, tom lane
> 
> 

=?UTF-8?B?QsO2c3rDtnJtw6lueWkgWm9sdMOhbg==?= <zboszor@pr.hu> writes:
> 2018-07-31 20:33 keltezéssel, Tom Lane írta:
>> Why?  Under what circumstances would xml2-config not be present
>> (assuming that libxml2 is) or give a less desirable answer than
>> pkg-config?

> The Yocto cross-compiler framework (since Yocto 2.2 IIRC) does not
> allow the "binconfig" scripts for XML2 and GD and for some other
> libraries.

Then that's a bug to fix in Yocto.  They can't imagine that their
shortcomings are grounds to force changes in every other software
on the planet.

            regards, tom lane