Re: Fix chdir-long.m4 caching

[Ralf Wildenhues]

Hello Eric-1,  ;-)

* Eric Blake-1 wrote on Tue, Sep 26, 2006 at 09:28:15PM CEST:
> 
> +# A little hack, as AT_CHECK_M4 already uses `stderr' to normalize it.
> +AT_CHECK_AUTOCONF([2>&1], [], [stdout])
> 
> Why not fix AT_CHECK_M4 instead?  This borrows from what I did for
> the M4 testsuite:

> --- tests/local.at    11 Sep 2006 16:42:57 -0000      1.35
> +++ tests/local.at    26 Sep 2006 19:24:38 -0000
> @@ -106,7 +106,7 @@
>       s/^autom4te: [^ ]*m4 /autom4te: m4 /
>       s/^autom4te: [^ ]*m4\.exe /autom4te: m4 /
>       s/ (E[A-Z]*)$//
> -    ' stderr]], [0],[$4])])
> +    ' stderr >&2]], [0], [], [$4])])

This triggers the multiple redirection bug on Ultrix (see
`(autoconf.info)File Descriptors'); I don't know if other, non-museum
systems are affected, too.  But anyway we disallow it in the manual, so
iff we decide that this is ok now, then at least both those doc parts
need updates, too:

|  -- Macro: AT_CHECK (COMMANDS, [STATUS = `0'], [STDOUT = `'], [STDERR =
|           `'], [RUN-IF-FAIL], [RUN-IF-PASS])
[...]
|      The COMMANDS _must not_ redirect the standard output, nor the
|      standard error.

IIRC there may also be somebody on the autoconf list who still likes to
build stuff on this system every once in a while, and report issues...

Cheers,
Ralf