Re: current glibc vs debian sid

[Roland McGrath]

Anyway, I think the better question is why should the behavior have changed
in this way instead of being compatible with how it has always been.  It
has always been blindingly obvious to me what the right thing to do is: 
Set build with config.guess unless --build is specified;
set host=build unless --host is specified;
set target=host unless --target is specified;
if target_alias != host_alias then decide you are building a cross compiler;
if `config.sub host` != `config.sub build` then decide you are cross-compiling.