minor, migrate to ggo->x,xh semantics

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, import coru library courtesy of cattle

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
hygiene, properly define XOPEN_SOURCE version

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/coru'

* feat/coru:
  hygiene, properly define XOPEN_SOURCE version
  minor, import coru library courtesy of cattle