FBE for Pixel 2

Includes various minor fixes for building in Android 8 trees with r23+ tag

Update FBE extended header in libtar to version 2 and include the entire
ext4_encryption_policy structure now after translating the policy.

See this post for more details:

Change-Id: I2af981e51f459b17fcd895fb8c2d3f6c8200e24b
diff --git a/libtar/encode.c b/libtar/encode.c
index c937152..1e679d8 100644
--- a/libtar/encode.c
+++ b/libtar/encode.c
@@ -16,6 +16,7 @@
 #include <pwd.h>
 #include <grp.h>
 #include <sys/types.h>
+#include <sys/sysmacros.h>
 # include <string.h>