Build libxz from external/xz-embedded.

Also add the various bits of Android tree detritus.

Bug: http://b/32846435
Test: builds
Change-Id: I520a6b37d4f66078b6d94f91f1208a84c2d5d9c4
diff --git a/README.version b/README.version
new file mode 100644
index 0000000..a9aaf07
--- /dev/null
+++ b/README.version
@@ -0,0 +1,2 @@
+URL: https://git.tukaani.org/?p=xz-embedded.git
+Version: 79b68de5657beecfad575578a7181cf6fca869cb