TODO: locale issues break the 'grep -P' in the info check. two
      things: (1) use a more reliable way to detect gz files, and
      (2) possibly force LANG and LC_* to "C". Or else en_US.UTF-8.
TODO: check ownership of executables? fail if >1000 uid or gid?
TODO: .manemptydirs.$$ doesn't get deleted
TODO: if package contains any static libs, don't suggest noarch.
TODO: stop checking shared libs for +x and being stripped if they're not
      directly in /lib /lib64 /usr/lib /usr/lib64. too many packages
      trigger this, and it just doesn't matter much.
TODO: dereference symlinks in icon permission test. probably some other
      perms tests, too.
TODO: figure out if /usr/GNUstep is allowed or not.
TODO: sbopkglint reports bad files in doc dir twice.
TODO: sbopkglint should check for stuff like /usr/lib/lv2 vs. /usr/lib64/lv2,
      according to ARCH. see audio/helm, v0.9.0, BUILD=1
TODO: sbopkglint could complain if the SlackBuild sets SLKCFLAGS
      but there's no native code.

Future test ideas:

- /usr/share/terminfo, light checking.

- duplicate files, maybe the error message could suggest a "ln -s" command
  to use if the file really does need to appear in multiple dirs.

- fonts. make sure they are what their filename says, and are installed to
  the correct /usr/share/fonts/* or /usr/share/kbd/consolefonts dir.

Other ideas:

When linting multiple packages, print a summary: 100 packages checked,
10 failed, 90 passed. Maybe with percentages too.

Clean up the output. Make it easier to grep.