Added check for the membarrier system call. Also added documentation about the new requirement.

rootfs/etc/logmonitor/notifications.d/membarrier/desc

@@ -0,0 +1,2 @@
+#!/usr/bin/with-contenv sh
+echo "$APP_NAME is likely to crash because it requires the membarrier system call.  See the documentation of this Docker container to find out how this system call can be allowed."

rootfs/etc/logmonitor/notifications.d/membarrier/filter

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+set -e # Exit immediately if a command exits with a non-zero status.
+set -u # Treat unset variables as an error.
+
+LINE="$1"
+
+if [ "$LINE" = "MEMBARRIER_CHECK_FAIL" ]; then
+    echo 'MEMBARRIER_CHECK_ACK' > /tmp/.firefox_membarrier_check
+    exit 0
+fi
+
+# No match found.
+exit 1
+
+# vim: set ft=sh :

rootfs/etc/logmonitor/notifications.d/membarrier/level

@@ -0,0 +1 @@
+WARNING

rootfs/etc/logmonitor/notifications.d/membarrier/title

@@ -0,0 +1,2 @@
+#!/usr/bin/with-contenv sh
+echo "$APP_NAME requires the membarrier system call."