Bug#884798: lintian could complain about pkg-config uses that fail to use

[Helmut Grohne <helmut@subdivi.de>]

Hi Chris,

On Fri, Dec 22, 2017 at 08:09:20PM +0000, Chris Lamb wrote:
>   https://anonscm.debian.org/git/lintian/lintian.git/commit/?id=70c81c7f1c9e96c8109988efe8aeca7ed17f122a
> 
> Let me know if you have any suggestions :)

Yes, I do.

The tag description suggests that pkg-config could have been invoked
directly. While that is a common way to fail cross compilation, the
pattern does not check that other case.

My original description suggested using another pattern

    (\$\(|`)pkg-config

for that other case matching the second paragraph of the tag
description. To see just how common this is, check:

https://codesearch.debian.net/search?q=path%3Aconfigure%5C.%5Bai%5D%5Bcn%5D+%28%5C%24%5C%28%7C%60%29pkg-config

I think you should remove the second paragraph from the description.
Flagging is probably better done in a separate tag (both of which can
and sometimes do happen in the same configure.ac).

I also wonder what the best advise actually is. Of course using
PKG_PROG_PKG_CONFIG is "best" in a sense, but it behaves subtly
different. The present use of AC_PATH_PROG gives choice of the variable
name and the value-for-absence to the user while the standard macro will
simply use PKG_CONFIG and an empty value. A number of scripts check
things like test "$PKG_CONFIG" = no and that would break when switching
the macro. On the other hand, using AC_PATH_TOOL in place of
AC_PATH_PROG is mostly risk-less, because it takes the very same
arguments and behaves in the same way (except for prepending
$ac_tool_prefix). So the better solution certainly is
PKG_PROG_PKG_CONFIG, but the riskless one certainly is AC_PATH_TOOL.

What are your thoughts here?

Helmut