C++ safety for leashdll.h

Signed-off-by: Kevin Wasserman <kevin.wasserman@painless-security.com>

(cherry picked from commit 0101affa062aa34398bd571740d8d84f6bf45d4d)

https://github.com/krb5/krb5/commit/8c26e24a41ca722eb55952865fee818c286a4824
Author: Kevin Wasserman <kevin.wasserman@painless-security.com>
Committer: Tom Yu <tlyu@mit.edu>
Commit: 8c26e24a41ca722eb55952865fee818c286a4824
Branch: krb5-1.10
 src/windows/leashdll/leashdll.h |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)