Eliminate dead stores.
In __mbsconv(), if prec was zero, nconv could have been used
uninitialized. Initialize it to a safe value so that there's no
chance of returning an error if stack garbage happens to be equal to
(size_t)-1 or (size_t)-2.
In svc_raw_reply(), don't leave stat uninitialized if the MSG_ACCEPTED
&& SUCCESS case succeeds. The stack garbage might be zero.
In clnt_raw_create(), avoid minor race condition initializing the
file-scope variable clntraw_private.
Found by: Clang static analyzer
28f2223875