[RFC] sema_wait_sig

[Oleksandr Tymoshenko]

Hello,

Is there any particular reason FreeBSD does not have sema_wait_sig
function? It seems to be easily implementable using cv_wait_sig
function. 

The reason I'm asking is that I'm getting some Linux drivers
ported to FreeBSD and the code in question relies on semaphores
and there is no obvious alternative to down_interruptible function.
I realize that not all approaches to driver development are easily
mappable from OS to OS but in this case lack of cv_wait_sig seems 
like gap in API. Unless of course there is strong rationale behind it.

Thank you