Re: Autoheader should ignore m4 "dnl" comments

[Kang-Che Sung]

On Fri, Feb 23, 2018 at 3:59 AM, Eric Blake <address@hidden> wrote:
> On 02/21/2018 08:07 PM, Kang-Che Sung wrote:
>>
>> This bug is a funny one, I think.
>>
>> In flex (lexer) configure.ac, I use "dnl" comments within
>> AC_CHECK_FUNCS for inline notes, like this:
>>
>>      # --------------------------------
>>      AC_CHECK_FUNCS([dnl
>>      pow dnl Used only by "examples/manual/expr"
>>      setlocale dnl Needed only if NLS is enabled
>>      reallocarr dnl NetBSD function. Use reallocarray if not available.
>>      reallocarray dnl OpenBSD function. We have replacement if not
>> available.
>>      ])
>
> Rather than waiting for an updated autoconf with the fix, you could instead
> workaround it in the meantime, by making it more obvious that your comments
> are just that:
>
> AC_CHECK_FUNCS(
> [pow ]dnl Used only by "examples/manual/expr"
> [seclocale ]dnl Needed only if NLS is enabled
> [reallocarr ]dnl NetBSD function. Use reallocarray if not available.
> [reallocarray ]dnl OpenBSD function. We have replacement if not available.
> )

I'm already aware that unquoting the argument will work, and thank you.
But I've proposed the workaround in Flex in a different way:
<https://github.com/westes/flex/pull/316/commits/08b34646bd51ce4ef9008b1c7de6dabe90700e48>

>
> Yeah, that's an unfortunate side effect of the current implementation, which
> treats AC_CHECK_FUNCS as a whitespace separated list of words and does NOT
> perform macro expansion on that list as you would expect.  It may be
> possible to fix autoconf, but the fix may be hairy; or it might not even be
> possible to fix, at which point, documentation would be the only thing to
> improve.
>

What I was complaining is the inconsistent behavior between generating
configure and generating config.h.in. Like I described in the follow-up mail,
I expect both files work or both files be broken the same way.