Warnings work in util/

Warnings work in util/

Make afs_ctime an inline function, instead of a complex macro.
This both improves our type safety, and suppreses warnings about
unused results.

Add bracing to clarify operator precedence in if (a && b || c)
statement

AFS_DARwiN60_ENV != AFS_DARWIN60_ENV

Use (void) rather than () in function prototypes

Reviewed-on: http://gerrit.openafs.org/240
Tested-by: Marc Dionne <marc.c.dionne@gmail.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>