System call ppoll is used on aarch64.
System call ppoll is used on aarch64.

My aarch64 GNU/Linux system with glibc uses ppoll before lock down
in stage 2 of sandbox. As poll is already supported there is no
harm in allowing ppoll as well.

Fixes aarch64-linux-gnu.

Signed-off-by: Tobias Stoeckmann <059b8b880f8441509ec8a65b50b4c6ae74ebea76@stoeckmann.org>

stoeckmann/xwallpaper,stoeckmann/xwallpaper