strace: Fix build issue with duplicate ptrace_peeksiginfo_args definition

Backport a patch from upstream to fix a conflict between glibc
headers and recent kernel headers (v3.10 or newer).

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Spenser Gilliland <spenser@gillilanding.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>