Make Alpha <sys/user.h> self-contained

[Joseph Myers]

The check-installed-headers tests show up that the Alpha <sys/user.h>
is not self-contained, using size_t without including any header that
defines it.  This patch fixes it by including <stddef.h>, as done for
other architectures' versions of this header.

Tested for Alpha (compilation only).

2016-11-04  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/unix/sysv/linux/alpha/sys/user.h: Include <stddef.h>.

diff --git a/sysdeps/unix/sysv/linux/alpha/sys/user.h b/sysdeps/unix/sysv/linux/alpha/sys/user.h
index 1a7c9c4..3d0d76b 100644
--- a/sysdeps/unix/sysv/linux/alpha/sys/user.h
+++ b/sysdeps/unix/sysv/linux/alpha/sys/user.h
@@ -23,6 +23,7 @@
    than gdb/strace unless you know what you are doing. */
 
 #include <asm/reg.h>
+#include <stddef.h>
 
 struct user
 {

-- 
Joseph S. Myers
joseph@codesourcery.com