The original commit introduced a bug by transposing the order of
some of the fields in xcb_size_hints_t. Since XCB ICCCM support is
required now, we can just eliminate the duplicate structs.
With minor changes:
- Remove #ifdef HAS_XCB_ICCCM guards
- Fix #includes
- Fix references to local size_hints struct
This reverts commit 12b9b1a4bd.