This introduces a sanity check for the toolchain, which verifies
each tuning (including any multilibs), producing meaningful diagnostics
for problems, and also provides some higher-level tuning features.
The TUNEVALID and TUNECONFLICT/TUNECONFLICTS settings were not
implemented. Listed one or two missing features in TUNEVALID,
also (in a previous patch) fixed the references to
features which didn't exist.
This patch also provides a whitelisting mechanism (which is completely
unused) to allow vendors providing prebuilt toolchain components to
restrict tunings to those based on or compatible with a particular ABI.
Signed-off-by: Peter Seebach <peter.seebach@windriver.com>
