I found the issue.

In r72899 antoine.pitrou checked in a change that adds these two lines 
to the bininstall target in Makefile.pre.in:

   -rm -f $(DESTDIR)$(LIBPC)/python3.pc
   (cd $(DESTDIR)$(LIBPC); $(LN) -s python-$(VERSION).pc python3.pc)

This exposes a bug in the configure script, which causes target 
'bininstall' to run before 'libainstall' when your doing a framework 
install.  The latter target is the one that creates python-
$(VERSION).pc, which is why we get build failures.

What I don't understand is why I've been able to install frameworks all 
along and didn't notice this before. 

I'm working on a patch, and will check that in after I've full tested 
it.

The important bit of the patch is this change to configure.in:

-		FRAMEWORKALTINSTALLFIRST="frameworkinstallstructure 
bininstall maninstall"
+		FRAMEWORKALTINSTALLFIRST="frameworkinstallstructure "