fcntl.h: define O_TTY_INIT to 0

POSIX: "[If] either O_TTY_INIT is set in oflag or O_TTY_INIT has the
value zero, open() shall set any non-standard termios structure
terminal parameters to a state that provides conforming behavior."

The Linux kernel tty drivers always perform initialisation on their
devices to set known good termios values during the open(2) call.  This
means that setting O_TTY_INIT to zero is conforming.

include/fcntl.h

@@ -36,8 +36,9 @@ int openat(int, const char *, int, ...);
 int posix_fadvise(int, off_t, off_t, int);
 int posix_fallocate(int, off_t, off_t);
 
-#define O_SEARCH  O_PATH
-#define O_EXEC    O_PATH
+#define O_SEARCH   O_PATH
+#define O_EXEC     O_PATH
+#define O_TTY_INIT 0
 
 #define O_ACCMODE (03|O_SEARCH)
 #define O_RDONLY  00