[toplevel] Gas install name problem from autoconf 2.5x

[Daniel Jacobowitz]

I've gotten a report that gas now installs after a native build as
$(target_alias)-as.  This is presumably the one consequence of autoconf
2.5x's "specify absolutely nothing on the command line unless absolutely
necessary" policy.

I see two basic choices:
  - Override AC_CANONICAL_TARGET.
  - Always pass down --program-transform-name from the top level.

I think the latter is the way to go.  Any other opinions?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer