Revision 526103

Update to 1.18

Abi is backward compatible: https://abi-laboratory.pro/tracker/timeline/wayland/
Port changes:
- Allow memfd_create on FreeBSD 13 for sealing
- Drop ms_timeout workaround in favor of upstream fix[1]
- Drop posix_fallocate patch as it was disabled in r455878
- Adjust posix_fallocate comment to improve clarity
- Temporarily revert event loop update until epoll-shim#15 [2] is fixed

[1]: https://gitlab.freedesktop.org/wayland/wayland/commit/75d14834570b
[2]: https://github.com/jiixyj/epoll-shim/issues/15

Build tested on:
    11.3 aarch64
    11.3 amd64
    11.3 armv6
    11.3 i386
    12.0 amd64
    12.0 i386
    12.1 aarch64
    12.1 amd64
    12.1 armv6
    12.1 armv7
    12.1 i386
    13.0 amd64
    13.0 i386
    Base GCC 4.2.1 (mimics powerpc*, mips*, riscv64)

Run tested with:
    multimedia/libva-intel-driver
    multimedia/mpv
    www/firefox + MOZ_ENABLE_WAYLAND
    x11-servers/xwayland-devel
    x11-wm/cage
    x11-wm/sway
    x11/wl-clipboard

PR:  244059
Submitted by: jbeich
Tested by: manu
Reviewed by: manu
Approved by: x11 (bapt)
Differential Revision: https://reviews.freebsd.org/D23643