MacPorts and clang

[Jack Howarth]

On Thu, Mar 03, 2011 at 09:48:40AM -0600, Ryan Schmidt wrote:
> 
> On Mar 3, 2011, at 09:40, Jack Howarth wrote:
> 
> >  Are there any plans to attempt to move MacPorts towards
> > building with clang once Xcode 4 is released? Considering that
> > we have so many packages supporting gcc4x variants to build with
> > FSF gcc, it seems strange not to do the same for clang.
> >             Jack
> > ps I assume that Xcode 4 won't be held up until Lion is released so
> > these clang variants could be first done on Snow Leopard. It is unclear
> > from http://developer.apple.com/technologies/tools/whats-new.html
> > if the clang c++ support in Xcode 4.0 will use the existing libstdc++
> > or the new libc++ instead. It would be nice if it were the latter.
> 
> Ports build with the standard Xcode gcc compilers unless there is a good reason not to. The reason why many ports have variants to use MacPorts gcc compilers is not because they particularly want to use the MacPorts gcc C or C++ compilers, but because they want to use a Fortran compiler, which Xcode doesn't provide.

   That wasn't my experience. When I contributed the pymol packaging, some of the other MacPorts
developers insisted on gcc4x variants despite the fact that pymol doesn't contain any fortran code.
A clang variant still might be a nice idea to provide a test bed for finding out which packages have
build issues and for filing reports or sending patches upstream. It is unclear from the published
information on Lion what Apple's intentions are for clang/libc++ but I am hoping they might be 
aggressive and, while building Lion with gcc-4.2, configure the standard system compilers to clang.
I believe we saw this done earlier in Mac OS X development (perhaps the gcc-3.3 to gcc-4.0
transition) where the Xcode defaulted to a newer gcc than was actually used to build the matching
OS release.
          Jack