Add MS_NOSYMFOLLOW flag

MS_NOSYMFOLLOW (since Linux 5.10) disallows automatic following of symlinks.

See: torvalds/linux@dab741e

(backport <rust-lang#4389>)
(cherry picked from commit 558f13c)

Author: tedbrandston

libc-test/semver/linux.txt

@@ -1732,6 +1732,7 @@ MS_NODEV
 MS_NODIRATIME
 MS_NOEXEC
 MS_NOSUID
+MS_NOSYMFOLLOW
 MS_NOUSER
 MS_POSIXACL
 MS_PRIVATE

src/unix/linux_like/mod.rs

@@ -627,6 +627,7 @@ pub const MS_SYNCHRONOUS: c_ulong = 0x10;
 pub const MS_REMOUNT: c_ulong = 0x20;
 pub const MS_MANDLOCK: c_ulong = 0x40;
 pub const MS_DIRSYNC: c_ulong = 0x80;
+pub const MS_NOSYMFOLLOW: c_ulong = 0x100;
 pub const MS_NOATIME: c_ulong = 0x0400;
 pub const MS_NODIRATIME: c_ulong = 0x0800;
 pub const MS_BIND: c_ulong = 0x1000;