x86inc: Support N_PEXT bit on Mach-O

Allows for marking symbols as having limited global scope, similar to
using 'hidden' symbol visibility on ELF.
16 jobs for master in 5 minutes and 30 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Style
passed #248837
amd64 debian
style-check

00:00:19

 
  Build
passed #248838
amd64 debian
build-debian

00:00:35

passed #248845
debian aarch64
build-debian-aarch64

00:01:16

passed #248846
debian aarch64
build-debian-aarch64-clang-5

00:01:05

passed #248839
amd64 debian
build-debian-static

00:00:33

passed #248848
debian aarch64
build-debian-werror

00:00:33

passed #248840
amd64 debian
build-debian32

00:00:26

passed #248847
macos
build-macos

00:00:31

passed #248843
win32
build-win-arm32

00:00:26

passed #248844
win64
build-win-arm64

00:00:29

passed #248841
win32
build-win32

00:00:31

passed #248842
win64
build-win64

00:00:35

 
  Test
passed #248849
amd64 debian
test-debian

00:00:44

passed #248850
amd64 debian
test-debian-asan

00:02:10

passed #248851
amd64 debian
test-debian-msan

00:00:59

passed #248852
amd64 debian
test-debian-ubsan

00:01:18