Re: fedora 42 doesn't have awk: how to deal with autoconf subst?

On 2025-04-17 04:31, Simon Josefsson wrote:
> Paul Eggert <[email protected]> writes:
>> [ awk cat cmp cp diff echo expr false
>> grep ls mkdir mv printf pwd rm rmdir
>> sed sort test touch tr true
> 
> Of those, I'm guessing awk, grep, sed and ls are the most complex.  The
> 'diff' tool also stands out, and most of my packages build fine (except
> for some spuriois error messages during ./configure) without 'diff', and
> it is often not available in containers.

In a minimal 'configure', if diff is absent then caches are ignored. 
This will slow things down but it won't break things.

However, many 'configure's will use diff in more-complicated ways. For 
example, when 'configure' checks whether 'grep' can handle long lines, 
if 'diff' is missing and grep lacks a --version flag, 'configure' will 
error out. This probably worked for you because you were using GNU grep 
which has --version, but it won't work in a minimal POSIX environment. 
And I imagine there are more-complicated dependencies on 'diff' in some 
'configure' files, where if 'diff' is missing 'configure' will configure 
your program incorrectly, perhaps merely hurting performance so 'make 
check' doesn't catch it.

In short, I wouldn't recommend running 'configure' without 'diff'.


> Having a limited/partial/inefficient awk implementation inside Autoconf,
> implemented in /bin/sh, for the functionality that Autoconf needs
> itself, would be nice.  It could be used if the system lacks 'awk'.  Or
> all code that rely on awk could be rewritten in shell syntax.

I don't offhand see how that would work, without significantly hurting 
performance in the usual case. But if someone could get it to work then 
yes it's better if 'configure' depends on fewer programs.

 From a minimalist point of view, Fedora's dropping of 'awk' in minimal 
containers should not be that big of a deal. If you want to build 
programs, you need build tools like gcc that really ought to be missing 
in minimal environments. Just add awk to build tool list.