apple: Correct the value of SF_SETTABLE

This was updated a long time ago in MacOS Catalina; update ours to
match.

Link: https://github.com/apple-oss-distributions/xnu/blob/f6217f891ac0bb64f3d375211650a4c1ff8ca1ea/bsd/sys/stat.h#L497

(backport <#4764>)
(cherry picked from commit db33ac4)

Author: tgross35

libc-test/build.rs

@@ -337,8 +337,6 @@ fn test_apple(target: &str) {
             // FIXME(deprecated): These OSX constants are removed in Sierra.
             // https://developer.apple.com/library/content/releasenotes/General/APIDiffsMacOS10_12/Swift/Darwin.html
             "KERN_KDENABLE_BG_TRACE" | "KERN_KDDISABLE_BG_TRACE" => true,
-            // FIXME(macos): the value has been changed since Catalina (0xffff0000 -> 0x3fff0000).
-            "SF_SETTABLE" => true,
 
             // FIXME(deprecated): Removed since 12.0.1 / xnu-8019.41.5. See `ttycom.h` at
             // https://github.com/apple-oss-distributions/xnu/commit/e6231be02a03711ca404e5121a151b24afbff733

src/unix/bsd/apple/mod.rs

@@ -4773,7 +4773,7 @@ pub const UF_APPEND: c_uint = 0x00000004;
 pub const UF_OPAQUE: c_uint = 0x00000008;
 pub const UF_COMPRESSED: c_uint = 0x00000020;
 pub const UF_TRACKED: c_uint = 0x00000040;
-pub const SF_SETTABLE: c_uint = 0xffff0000;
+pub const SF_SETTABLE: c_uint = 0x3fff0000;
 pub const SF_ARCHIVED: c_uint = 0x00010000;
 pub const SF_IMMUTABLE: c_uint = 0x00020000;
 pub const SF_APPEND: c_uint = 0x00040000;