Add missing TIOCGETA/TIOCSETA constants for macOS

- Add TIOCGETA (0x40487413) for getting termios state
- Add TIOCSETA (0x80487414) for setting termios state immediately
- Add TIOCSETAW (0x80487415) for draining output then setting
- Add TIOCSETAF (0x80487416) for draining output, flushing input, then setting

These constants are present in macOS system headers but were missing
from the libc crate. Fixes issue #4735.

(backport <#4736>)
(cherry picked from commit 755613e)

Author: mmastrac

src/unix/bsd/apple/mod.rs

@@ -3341,6 +3341,10 @@ pub const TIOCDSIMICROCODE: c_uint = 0x20007455;
 pub const TIOCPTYGRANT: c_uint = 0x20007454;
 pub const TIOCPTYGNAME: c_uint = 0x40807453;
 pub const TIOCPTYUNLK: c_uint = 0x20007452;
+pub const TIOCGETA: c_ulong = 0x40487413;
+pub const TIOCSETA: c_ulong = 0x80487414;
+pub const TIOCSETAW: c_ulong = 0x80487415;
+pub const TIOCSETAF: c_ulong = 0x80487416;
 
 pub const BIOCGRSIG: c_ulong = 0x40044272;
 pub const BIOCSRSIG: c_ulong = 0x80044273;