arm64: Add thread exit syscall in commpage.

Change-Id: Ia8e7e4626add623735fefefa1af151b7338adc35
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5265
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

arm64: Add more headers for code compilation

This makes ARM64 target compile more files. This patch is one of
series of patches to support new architecture, as fixes in many
places are required just to compile the code.

Signed-off-by: Jaroslaw Pelczar <jarek@jpelczar.com>
Change-Id: Ia060612733cd3a0fcb781fec449da164ed635b8e
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1807
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>