> 2) How to build the appropriate sets of libraries?  As far as I can tell, 
> libc can only be built once.  Is there a way to build another version of 
> libc (with a different name, or installed in a different sub-dir) with a 
> different set of compiler flags?
...
> I'm not sure exactly what the solution to 2) is, but my guess is that it's 
> largely a matter of makefile hackery.  Maybe it is just a matter of 
> splitting the makefile up into a body that defines the files to compile 
> and a wrapper (or series of wrappers) that define the build options.

It ought to be possible to use reach-over make rules to build
the sources of libc into a different object subdirectory.
(a bit like what happens with crunchgen)

	David

-- 
David Laight: david@l8s.co.uk