On 2014-02-27 02:00, Peter Rosin wrote:
> On 2014-02-27 01:38, Russ Allbery wrote:
>> Peter Rosin <p...@lysator.liu.se> writes:
>>> On 2014-02-27 01:20, Russ Allbery wrote:
>>
>>>> Wouldn't you name the variable FOO_FEATURE? In other words, I think
>>>> the example in the Autoconf manual is not the best, but the
>>>> functionality you need is there. I would rewrite the example as:
>>>>
>>>> AC_CACHE_CHECK([for m4 that supports indir], [ac_cv_path_M4_indir],
>>>> [AC_PATH_PROGS_FEATURE_CHECK([M4_indir], [m4 gm4],
>>>> ...
>>>> AC_SUBST([M4], [$ac_cv_path_M4_indir])
>>
>>> That doesn't work, because then you can't shortcut the test with the
>>> natural M4=/some/gnu/place/m4, you'd be forced to write M4_indir=...
>>> instead. This is even worse than saving the ac_cv_path_FOO variable
>>> during the AC_PATH_PROGS_FEATURE_CHECK macro, since it would be visible
>>> to the end user.
>>
>> Good point. However, couldn't you just put:
>>
>> : ${ac_cv_path_M4_indir:=$M4}
>>
>> before the above code?
>
> Good point. Or put
>
> : ${M4_indir:=$M4}
>
> just before AC_PATH_PROGS_FEATURE_CHECK... Ho humm, which is best? Do I
> want to see (cached) when overriding in the environment? Or not?
I think ": ${M4_indir:=$M4}" is slightly better, because then
M4_indir=/gnu/stuff/m4 beats M4=/crappy/shit/m4 while
ac_cv_path_M4_indir=/goodness/m4 still trumps both of them.
But that's probably of little practical importance...
Cheers,
Peter
