Support building all variants.

Bug: 143217452
Test: cd external/rust; mma; atest in all TEST_MAPPING subdirs
Change-Id: Ib5f2d36c937bc0b61b3c417a500a53a3a897491b
diff --git a/Android.bp b/Android.bp
index 14e8126..b0c553f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,6 +1,6 @@
 // This file is generated by cargo2android.py.
 
-rust_library_host_rlib {
+rust_library_host {
     name: "libregex",
     crate_name: "regex",
     srcs: ["src/lib.rs"],
@@ -25,7 +25,7 @@
         "unicode-script",
         "unicode-segment",
     ],
-    rlibs: [
+    rustlibs: [
         "libaho_corasick",
         "libmemchr",
         "libregex_syntax",