The order of the blocks matter. If "nil" is the first, later modes
won't overwrite variables already defined.

Additionally, whitespace variables won't take effect if the mode is
not yet activated.

Signed-off-by: Andres Gomez <agomez@igalia.com>
Acked-by: Ilia Mirkin <imirkin@alum.mit.edu>
Part-of: <mesa/piglit!347>