Adding configure options when installing a port

[Ryan Schmidt]

On Jun 17, 2010, at 14:05, Scott Webster wrote:

> On Thu, Jun 17, 2010 at 11:44 AM, Ryan Schmidt <ryandesign at macports.org> wrote:
>> On Jun 16, 2010, at 19:31, Stephen Langer wrote:
>> 
>>> Therefore it's a serious mistake for a packaging system to assume that it's ok to enable openmp in libraries.   A quick solution would be to provide both openmp and no-openmp variants, which would make users choose between fast stand-alone ImageMagick programs and libraries that can be linked by threaded apps.
>> 
>> We don't need two variants; we only need one variant, "openmp", which the user can either enable or disable. It just remains a question as to whether the variant should be enabled by default or not. What I'm hearing is that we should disable it by default.
>> 
> 
> I'm not entirely sure I agree with disabling by default.  Unless I was
> reading this list, I would never have known about this issue, and
> would just go with the default.  Disabling openmp would slow down
> everything (well, not quite everything I guess) I do with ImageMagick
> by a factor of 2.  Same would happen with other ports that can use
> openmp if it was disabled there...
> 
> I guess I'm just saying that there is a trade-off between universal
> compatibility and speed here.  I don't have a good handle on how big
> of an issue the compatibility thing is.  If it's quite isolated then I
> think having the twice (or more) as fast option as default is
> reasonable.

Users are expected to read the output of "port variants" to decide if they might want to use any of those variants...