Fix broken functional test.

In Lua, all math is floating point.  We need to coerce the result of a
division into a integer with the `{get,set}_height` and
`{get,set}_width` window_spec functional tests.
deps: Update bundled lua client version

The new version fixes defunct processes which causes random test failures on
some systems(#1519)
Merge PR #1547 'Update bundled lua client version'
Add missing refcount increment for systemlist()

- get_system_output_as_rettv() was missing a refcount increment when
  returning an empty list, i.e. when there was no output
- we now use rettv_list_aloc() instead of list_alloc()
- issue #1530
Merge pull request #1552 from equalsraf/tb-fix-1530

add missing refcount increment for systemlist()
Merge pull request #1543 from jszakmeister/fix-broken-functional-tests

Fix broken functional test.
Remove NeXTSTEP references

Remove trailing whitespace as well.
Remove Atari MiNT references
Remove OS/2 references

Paul Slootman was removed from the top of os_unix.c as OS/2 is no longer
supported, but is still credited in runtime/doc/intro.txt.