Re: configure scripts rely on "diff"; could use "cmp" instead if available

[Eric Blake]

On 05/25/2011 06:40 AM, Konstantin Andreev wrote:
> On 24.05.11 22:43, Eric Blake wrote:
>> On 05/24/2011 11:41 AM, Josh Triplett wrote:
>>> <...>  The version of busybox-static in Debian doesn't provide diff,
>>> but does provide cmp.
>>
>> That's in conflict with the current GNU Coding Standards, which states
>> that a program can blindly assume the existence of diff on $PATH.
> 
> Why do you refer to GCS? I thought that 'autoconf' is intended for most
> Unix'es, not only GNU.

Autoconf stated goal is to generate configure scripts that run on all
platforms that comply with the GCS set of minimum prerequisites - it so
happens that this covers most Unix'es (including proprietary systems).
But right now, the GCS lists diff as a pre-installed minimum
prerequisite, so your busybox is NOT in the set of most Unix'es that
support autoconf scripts out of the box.  Either GCS is too strict, and
should be relaxed, or your busybox setup should start providing diff, or
both.  But since busybox is open source, my guess is that rms will be
somewhat reluctant to change GCS to remove the diff prerequisite, and
instead request that busybox come up to par with the rest of the Unix
world by providing diff as a prerequisite.

I recall a previous incident where the MSYS platform was lacking a
program from the GCS prereqs (although I don't recall which program);
the solution back then was to add the program to MSYS, rather than
changing the GCS and making autoconf work around the lack of that
prereq.  However, I don't have a URL handy for that discussion.

-- 
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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