ia64: include errno.h in sysdep.h

This header uses __set_errno(), so make sure we include errno.h for it.
Otherwise, if INLINE_SYSCALL() is used and errno.h isn't included, we
hit warnings like so:
In file included from libc-start.c:36:0:
../sysdeps/unix/sysv/linux/dl-osinfo.h: In function '_dl_setup_stack_chk_guard':
../sysdeps/unix/sysv/linux/dl-osinfo.h:79:7: warning: implicit declaration of function '__set_errno'

Which culminate in errors like so:
libc-start.c:(.text+0x692): undefined reference to '__set_errno'
libc-start.c:(.text+0x752): undefined reference to '__set_errno'
collect2: ld returned 1 exit status

Reported-by: Dennis Schridde <devurandom@gmx.net>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

ChangeLog.ia64

@@ -1,3 +1,7 @@
+2012-05-07  Mike Frysinger  <vapier@gentoo.org>
+
+	* sysdeps/unix/sysv/linux/ia64/sysdep.h: Include errno.h.
+
 2012-05-06  Mike Frysinger  <vapier@gentoo.org>
 
 	* data/localplt-ia64-linux-gnu.data: New file.

sysdeps/unix/sysv/linux/ia64/sysdep.h

@@ -25,6 +25,11 @@
 #include <dl-sysdep.h>
 #include <tls.h>
 
+/* In order to get __set_errno() definition in INLINE_SYSCALL.  */
+#ifndef __ASSEMBLER__
+#include <errno.h>
+#endif
+
 /* As of GAS v2.4.90.0.7, including a ".align" directive inside a
    function will cause bad unwind info to be emitted (GAS doesn't know
    how to account for the padding introduced by the .align directive).