muniversal port group

[Joshua Root]

On 2018-2-10 07:04 , Joshua Root wrote:
> On 2018-2-10 06:14 , David Strubbe wrote:
>> Hello all,
>>
>> I have a question about the muniversal port group, motivated by
>> examining what happens with its usage in the fftw-3 port. If the
>> +universal variant is selected, then appropriate values of
>> configure.args are set for different architectures via
>> merger_configure_args, which in the case of fftw-3 includes flags about
>> whether support for certain vector intrinsics like SSE2 and AVX will be
>> compiled. However, if +universal is not selected, then these flags are
>> simply not used, rather than selecting the appropriate flag for the
>> single architecture we are building for. As a result, currently in
>> fftw-3, we are only enabling appropriate intrinsics for the architecture
>> when doing +universal, and otherwise we have no intrinsics support.
>>
>> How is this supposed to work with the muniversal port group? Are flags
>> needed when not +universal not expected to be set in this merger array?
>> Is this a limitation of the port group that should be extended? Is there
>> some option to set in the port group which I have missed?
> 
> The muniversal portgroup is not involved at all if you're not building
> with +universal. If you need to set certain flags in the non-universal
> case, just do it.

Looking at the Portfile, there appears to be code to set these sorts of
flags in the non-universal case in the fftw-3-single subport, but none
in the main fftw-3 port or the fftw-3-long subport.

- Josh