Potential problem with small subset of Cocoa ports on Xcode 10

[Chris Jones]

> On 28 Sep 2018, at 10:55 pm, Perry E. Metzger <pmetzger at macports.org> wrote:
> 
> On Sat, 29 Sep 2018 07:40:22 +1000 Joshua Root <jmr at macports.org>
> wrote:
>>>> Here's the kludge for a Portfile:
>>>> 
>>>> if {[vercmp ${xcodeversion} 10.0] >= 0} {
>>>>   destroot.pre_args   -UseNewBuildSystem=NO
>>>> }
>>>> 
>>>> Arguably, one should do "= 0" rather than ">=" since the bug may
>>>> be fixed in Xcode 10.whatever.  
>>> 
>>> That would depend on whether you are correct or not in saying its
>>> a bug in Xcode. If it isn’t making it an equality will just mean
>>> the ports start failing again when Xcode is updated.  
>> 
>> The header search strategy change is not a bug. The failure when
>> building and destrooting separately is definitely a bug, and can be
>> reproduced even with a new project using the Cocoa App template.
> 
> BTW, that's why I set this up only to do the UseNewBuildSystem=NO
> during destroot and not during build. Fixing the search stuff for
> build seems sane.

Hmm... is it really ok to switch the build settings between build and destroot ? I would have guessed it better to be consistent for all phases. 

> 
> Perry
> -- 
> Perry E. Metzger        pmetzger at macports.org