Re: [PATCH] warnings.m4: provide a means to specify the program to compile

[Jim Meyering]

Jim Meyering wrote:
> Akim Demaille wrote:
...
>> The attached patch enhances warnings.m4 in several ways:
>>
>> - gl_COMPILER_OPTION_IF allows to define more fine grain tests on the
>>   behavior of the compiler.  Forcing the result to be an assignment to
>>   a variable (which is AC_SUBST'ed) does not seem to offer the
>>   orthogonal design one would expect.  This would be useful elsewhere,
>>   for instance in manywarnings, as I have already reported
>>   (http://lists.gnu.org/archive/html/bug-gnulib/2012-03/msg00198.html)
>>
>> - separating the diagnostic part from the action part provides a
>>   cleaner way to implement test cases.
>>
>> - separating the diagnostic part from the action part helps extending
>>   both in a cleaner way:
>>
>>   - it allowed me to cleanly integrate the missing AC_SUBST for
>>     WARN_CFLAGS instead of leaving this to modules/warnings
>>
>>   - it will make it easier to check for the answers of the compiler on
>>     stderr (as currently, we merely check whether the compiler rejects
>>     the candidate option with an error status; this results in uselessly
>>     long compilation command lines, and spurious warnings in some
>>     situations).
>>
>> - the added parameter to gl_WARN_ADD allows to fine tune whether a
>>   given warning is wanted or not (e.g., 0 vs. nullptr as above).
>
> I like the patch.
> If no one objects, I'll push it later today.

Pushed.