MFC	r268642:
libc/gen: small updates to code originating at OpenBSD

arc4random.c
- CVS rev. 1.22
Change arc4random_uniform() to calculate ``2**32 % upper_bound'' as
``-upper_bound % upper_bound''. Simplifies the code and makes it the
same on both ILP32 and LP64 architectures, and also slightly faster on
LP64 architectures by using a 32-bit remainder instead of a 64-bit
remainder.
- CVS rev. 1.23
Spacing

readpassphrase.c
-CVS rev. v 1.24
most obvious unsigned char casts for ctype

Obtained from:	OpenBSD
MFC	r268644:
libc/stdlib: Minor cleanups to code originating in NetBSD

Mostly ANSIfication and typos.

Obtained from:	NetBSD
MFC	r268798, r268799, r268801:
grep: Fix type.
grep: fix some memory leaks.

queue.c (CVS Rev. 1.4. 1.5)
Fix memory leaks.
NULL does not need a cast.

grep.c (CVS Rev. 1.6)
Use the more portable getline.

Obtained from:	NetBSD