build_arch vs. configure.build_arch

[Bryan Blackburn]

On Sun, Sep 06, 2009 at 04:13:31PM -0500, Ryan Schmidt said:
> 
> On Sep 6, 2009, at 14:44, Bryan Blackburn wrote:
> 
> >On Sun, Sep 06, 2009 at 07:48:32AM -0500, Ryan Schmidt said:
> >>What is the difference between build_arch and configure.build_arch?
> >>Which should we compare against in Portfiles when we want to know?
> >>Which should we set when we want to force the build one way or
> >>another?
> >
> >configure.build_arch defaults to whatever build_arch is:
> >
> ><http://trac.macports.org/browser/trunk/base/src/port1.0/portconfigure.tcl#L154
> >>
> 
> So, why are there two variables, and which one should we use?

configure.build_arch, just like the other configure.* variables; since
build_arch is meant to be settable from macports.conf, it shouldn't have to
worry about which target is used when a port is actually built.  But from a
Portfile, you do worry about that, hence configure.build_arch (which, since
it uses the default/options setup, can also be changed).

> 
> 
> >>Is there an easy way to say "this port doesn't support 64-bit" or do
> >>we have to do the "if x86_64 is requested then use i386 else if ppc64
> >>is requested then use ppc" dance?
> >
> >The problem with this is, what do we do about dependencies?  If port B
> >depends on A, and A was built 64bit but B says "I only do 32bit",
> >then what?
> 
> I don't care about dependencies right now; that's #20728.
> 
> http://trac.macports.org/ticket/20728
> 
> I guess my request for an easy way to indicate that only 32-bit is
> supported is the "archs i386 ppc" syntax proposed here:
> 
> http://trac.macports.org/ticket/20739
> 
> I'll just do it the long way for now, like the other ports have been
> doing it.
> 
> http://trac.macports.org/changeset/56602

It's definitely going to be messy until someone improves the way we handle
arch/universal in a more general way...

Bryan