Minor AIX packaging enhancements.

- Try sudo if /usr/sbin/mkinstallp is not executable directly
  (packaging as a non-root user)
Merge pull request #36 from aleibl/develop

Minor AIX packaging enhancements.
Multiple security changes.

- Fixed incorrect size calculation which resulted in a potential buffer overflow
- Switched to _s methods for windows for added safety
- replaced incorrect sizeof operators with strlen