Problem subdir configures get run again after toolchain built if make repeated.

[Graham Stott]

Hi Nathanael, DJ

There appears to be a problem in recent changes to configure and build process
in the Uberbaum tree.

After successfully configuring and building a toolchain (ie. running configure
then make) I find that running make again afterwards with no changes or updates
results in configure being runing again in many but not all subdirs.

This happens on all toolchains I've tried so far. I don't know when this behaviour
first appeared but it's likely to be sometime in the last two weeks.

The powerpc-eabi target is one I've tried which shows the problem.

Cheers
Graham