scripts/diffconfig.sh: ensure config/conf is built
diffconfig.sh runs ./scripts/config/conf, but it does not get built
with 'make {menu,x,n}config. Call 'make ./scripts/config/conf' to
ensure it's been built before running it, aborting in case of failure.
Signed-off-by: Eneas U de Queiroz <[email protected]>
Signed-off-by: Petr Štetiar <[email protected]>[removed Fixes: due revert]