111.25.00

- Added `Gc.disable_compaction` function.
- Added `Time.to_string_abs_trimmed`, which prints a trimmed time and
  takes a `zone` argument.
- Fixed `unix_stubs.c` to suppress a warning when building with some
  versions of gcc.
- Changed `Time.Zone` to allow the zoneinfo location to be specified
  by an environment variable.

  Closes #40
- Fix compatibility with 4.02