Re: [PATCH 1/2] Fix detection of GNU M4 on mksh

[Zack Weinberg]

On Sun, Oct 15, 2023, at 2:58 AM, KO Myung-Hun wrote:
> Zack Weinberg wrote:
>> On Sat, Oct 14, 2023, at 9:19 AM, KO Myung-Hun wrote:
>>> * m4/m4.m4 (AC_PROG_GNU_M4): Double-quotes $ac_snip2.
>> Please explain why it isn't also necessary to add double quotes
>> around all the other variable expansions in this check, particularly
>> $ac_snippet and $ac_path_M4.
>
> Because this test fails due to $ac_snip2

Details please?

> Anyway I've double-quoted $ac_snippet, too.

I think that's the right thing just as a general defensive measure.

> However, not required to $ac_path_M4, which does not contain NL.

Hmm. I want to say "how do you know it will _never_ contain an IFS
character" but probably Autoconf doesn't handle whitespace in the full
pathnames of programs reliably _anywhere_ and in fact that feature would
conflict with being able to do things like

    M4="gm4 -E" autoconf

so let's leave $ac_path_M4 as is.


zw