Moving build.* files under platforms/$OS/$ISA

 
Eliot,

The build.* files at the top level are crowding out the main code
directories and it will only get worse with more platforms joining in.

Wouldn't it be better to move them under platforms/$OS/$ISA/ with a
shorter name? E.g.
    build.linux32x64 ->platforms/unix/x64/build

A Makefile at the top level can detect the platform and switch to the
respective sub-directory for the build. The products can also be
generated under the respective platform dirs leading to simpler names
like cogspur instead of cogspurlinuxht etc.

I am not sure if this option has been considered before.

Regards .. Subbu