Avoid using reserved identifiers such as `_DOHINT_H` (fixes #1989), fix cases where the name doesn't match the filename, and make the naming more consistent and less likely to collide with include guards in other headers.
git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@7519 626c5289-ae23-0410-ae9c-e8d60b6d4f22