Small fixes:
1.) Comment out "MASTER_SITES". The URL no longer works and all copies
    that Google can find are "pkgsrc" distfile mirrors.
2.) Fix various "pkglint" errors.
Don't segfault when using PKG_OPTIONS.libVNCServer=-inet6
Maintainer mode was being activated in all cases, which is not
desirable; in particular on builds it enables -Werror which causes
the build to fail now.  from Debian by way of FreeBSD.