MAINT: Don't use absolute paths for running configure

This causes configure to use absolute paths for access to source code
which is known to break at least novaprova.

Reviewed-by: John Collis <john.collis@alliedtelesis.co.nz>

Signed-off-by: Andrew Campbell <andrew.campbell@alliedtelesis.co.nz>
MAINT: colorize warnings/errors

This makes it easier to see errors, warnings etc especially with the
huge output from parallel compiling.

Reviewed-by: Brad Carthew <brad.carthew@alliedtelesis.co.nz>