Import of code from heimdal

This commit updates the code imported from heimdal to
5dfaa0d10b8320293e85387778adcdd043dfc1fe (git2svn-syncpoint-master-311-g5dfaa0d)

Upstream changes are:

Ben Kaduk (1):
      Be friendly to krb5_generate_random_block consumers

Jeffrey Altman (6):
      roken: include limits.h unconditionally
      Avoid unused variable warning on Windows
      roken: include direct.h if HAVE_DIRECT_H
      roken: Define S_IRWXU and friends on Windows
      roken: Add rk_mkdir()
      libkrb5: Add missing KRB5_LIB_FUNCTION/KRB5_LIB_CALL

New files are:
	krb5/crypto-algs.c
	krb5/crypto-arcfour.c
	krb5/crypto-des-common.c
	krb5/crypto-des.c
	krb5/crypto-des3.c
	krb5/crypto-null.c
	krb5/crypto-rand.c
	roken/mkdir.c

Reviewed-on: http://gerrit.openafs.org/10045
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Simon Wilkinson <simonxwilkinson@gmail.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 6c6e01a87fd58d09c1b8f6022e43b6d2bb9f4f73)

Change-Id: I16b28382f5979e2f595686f28c4db05e97eb81f5
Reviewed-on: http://gerrit.openafs.org/10056
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>