build: make wafsamba CHECK_SIZEOF cross-compile friendly

build: make wafsamba CHECK_SIZEOF cross-compile friendly

Use the same trick as commit 0d9bb86293c9d39298786df095c73a6251b08b7e
We do the same array trick iteratively starting from 1 (byte) by powers
of 2 up to 32.

The new 'critical' option is used to make the invocation die or not
according to each test.
The default is True since normally it's expected to find a proper
result and should error out if not.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: David Disseldorp <ddiss@samba.org>