[sudo-workers] Bug 641 - Add ability to link with system sha2 library instead of custom implementation

[Vladimir Marek]

Hi guys,

I just opened new enhancement request #641. I have implementation which
is good enough for Solaris, but I would like to make it into official
tree. I would like to ask you to take a look at the patch and let me
know what would have to be changed/improved to have the change included
in sudo.

Thank you!
-- 
	Vlad