Log Message:
Convert to the bsd.pkg.install.mk framework:
- Honour PKG_SYSCONFDIR.
- Automatically install configuration file from sample directory.
- Use RCD_SCRIPTS to automatically handle the rc.d script.
- MESSAGE is not needed because of the above two points (standard messages
  are used).

While here, avoid overriding CFLAGS while building and use the right C++
compiler (from CXX's value).

Bump PKGREVISION to 1.