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

membarrier_check.c

@@ -0,0 +1,14 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <linux/membarrier.h>
+#include <sys/membarrier.h>
+
+int main()
+{
+    int rc = membarrier(MEMBARRIER_CMD_QUERY, 0);
+    if (rc < 0) {
+        perror("membarrier");
+        exit(EXIT_FAILURE);
+    }
+    exit(EXIT_SUCCESS);
+}