uml: move remaining useful contents of user_util.h

Rescue the useful contents of the soon-to-be-gone user-util.h.

pty.c now gets ptsname from stdlib.h like it should have always done.

CATCH_EINTR is now in os.h, although perhaps all usage should be under
os-Linux at some point.

get_pty is also in os.h.

This patch restores the old definition of ARRAY_SIZE in user.h.  This file is
included only in userspace files, so there will be no conflict with the
kernel's new ARRAY_SIZE.  The copy of the kernel's ARRAY_SIZE and associated
infrastructure is now gone.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 22666b4..394adcd 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -16,6 +16,8 @@
 #include "sysdep/tls.h"
 #include "sysdep/archsetjmp.h"
 
+#define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR))
+
 #define OS_TYPE_FILE 1
 #define OS_TYPE_DIR 2
 #define OS_TYPE_SYMLINK 3
@@ -341,6 +343,10 @@
 extern void sig_handler_common_skas(int sig, void *sc_ptr);
 extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
 
+/* sys-x86_64/prctl.c */
 extern int os_arch_prctl(int pid, int code, unsigned long *addr);
 
+/* tty.c */
+int get_pty(void);
+
 #endif