Xcode universal

[Ryan Schmidt]

nox,

I've seen you do this a lot recently:

-use_configure	no
+# Dummy configure to enable universal variant
+use_configure	yes
+configure		{}

And this:

+if {! [variant_isset universal]} {
+	set arch ${os.arch}
+	if {! [string compare ${arch} powerpc]} {
+		set arch ppc
+	}
+
+	xcode.build.settings-append		ARCHS=${arch}
+	xcode.destroot.settings-append	ARCHS=${arch}
+}

I see those blocks in 9 ports so far, and I'm concerned about the  
duplication of code. Would it make sense to move this kind of thing  
into MacPorts base or the Xcode portgroup? Perhaps relevant is this  
existing ticket:

http://trac.macosforge.org/projects/macports/ticket/11881

If there is a way that we can sanely support universal and non- 
universal builds for ports in the Xcode portgroup automatically, then  
we should do so automatically, rather than individually in each port.