Re: m4-1.4.7: inconsistency in src/m4.h

[Eric Blake]

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According to Martin Koeppe on 10/14/2006 7:33 PM:
> 
> I now see your point. But yes, if for cygwin it is absolutely ok to have
> __unix__, then for interix it's double absolutely ok to have __unix__
> :-). interix, which should be seen as just another unix, is much more
> POSIX conformant than cygwin as far as the kernel is concerned. You have
> a case sensitive file system, chroot() and SETUID bits for example. The
> userland, well ..., that's why I build m4 for it, to get it better :-)

Actually, cygwin has a case sensitive file system (and cygwin, unlike
interix, even has the notion of a managed mount where you can name files
with characters or names that Windows otherwise forbids), chroot, and
setuid.  Not that any of those features are relevant to building m4.

>>>> By the way, M4 can include <unistd.h> blindly, thanks to gnulib
>>>> portability code (and in fact, already does so, via "unistd--.h"). 
>>>> There
>>>> is no need to check for HAVE_UNISTD_H, only to rearrange the
>>>> gnulib header inclusion to occur prior to the platform macro detection
>>>> section.
> 
> This one I don't yet understand. Looking at "unistd--.h" shows that
> <unistd.h> is also included unconditioned. Maybe the test should be made
> here? I couldn't find any file named "unistd.h" in m4's source which
> could be included instead, if the system doesn't have one.
> So what will happen if you "delete" your system's <unistd.h> before
> building m4?

You get what you deserve if you go deleting system headers.  The gnulib
project has found that all modern systems worth porting GNU tools to
already provide <unistd.h>, so it is no longer worth wasting the time to
check for its existence.  And if a viable porting target is presented that
does not meet this assumption, it is trivial within the gnulib framework
to provide a replacement unistd.h, which will benefit more than just m4,
since several other GNU projects use gnulib.  M4, by using gnulib's
unistd--.h, benefits from this wealth of portability project.

> 
> And if <unistd.h> is absolutely needed, then configure should stop when
> not finding it, saying that platforms without it aren't supported,
> shouldn't it? At least as it checks for it...

Until you actually demonstrate a viable platform that lacks <unistd.h>,
this is a theoretical point not worth worrying about.

> 
>> Here's what I'm installing.  Let me know if you would be willing to try a
>> snapshot tarball on Interix before I release 1.4.8 in the next few weeks.
> 
> Yes, sure I can / am willing to do that.
> 

Okay, I will send you an off-list URL of a snapshot.

- --
Life is short - so eat dessert first!

Eric Blake             address@hidden
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