Re: [sr #110215] AC_EGREP_HEADER appears to be broken in master

On 2020-03-24, Ross Burton <[email protected]> wrote:
> As to why this is not broken with 2.69, I think I have a theory.
>
> If I build e.g. acl with both 2.69 and master, it's notable that 2.69
> has these lines in the output that do not exist in master:
>
>> checking how to run the C preprocessor... gcc  -E
>> checking for grep that handles long lines and -e...
>> /scratch/poky/hosttools/grep
>> checking for egrep... /scratch/poky/hosttools/grep -E
>> checking for ANSI C header files... yes

Probably that is it: the long-obsolete AC_HEADER_STDC, previously
used internally by AC_INCLUDES_DEFAULT, used AC_EGREP_HEADER.  The
AC_HEADER_STDC macro is now a no-op (and is not used at all within
Autoconf anymore), so that change is likely what made the first use
of AC_EGREP_HEADER the one inside the if condition, causing the
observed results.

> Something else was causing the egrep search to happen early in the
> build.  My hunch is that the same codepath exists in apt, and now
> isn't expanding egrep earlier in the configure run.
>
> Thanks for the explanation, I'll switch out if for AS_IF and move on.

Sounds great.  And thanks for all your effort in testing and fixing all
these packages.

Cheers,
  Nick