Import of code from heimdal

Import of code from heimdal

This commit updates the code imported from heimdal to
0cc7b890e2632a7cb26517825deb802f79e838f8 (switch-from-svn-to-git-1702-g0cc7b89)

Upstream changes are:

Asanka C. Herath (3):
      Annotate exported variables in getopt.c
      Windows: Support building roken as a DLL
      Declarations for getopt externs

Simon Wilkinson (1):
      roken: getopt should include roken.h

Change-Id: I5ef850bcac7dace3a8206958783ed6fd5830492e
Reviewed-on: http://gerrit.openafs.org/3378
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>