Make GNU tar ignore the apk-tools header fields

This should problably not be upstreamed

--- ./src/xheader.c.orig
+++ ./src/xheader.c
@@ -1779,7 +1779,10 @@
   /* We are storing all extended attributes using this rule even if some of them
      were stored by some previous rule (duplicates) -- we just have to make sure
      they are restored *only once* during extraction later on. */
-  { "SCHILY.xattr", xattr_coder, xattr_decoder, 0, true },
+  { "SCHILY.xattr", xattr_coder,  xattr_decoder, 0, true },
+
+  /* Ignore apk-tools headers */
+  { "APK-TOOLS.", dummy_coder, dummy_decoder, 0, true },
 
   { NULL, NULL, NULL, 0, false }
 };