Support building all variants.

Bug: 143217452
Test: cd external/rust; mma; atest in all TEST_MAPPING subdirs
Change-Id: Iae82698e06275d4839cdaab8cc35bc9c2928b70e
diff --git a/Android.bp b/Android.bp
index c519e1f..dce00a0 100644
--- a/Android.bp
+++ b/Android.bp
@@ -5,7 +5,7 @@
     crate_name: "paste_impl",
     srcs: ["src/lib.rs"],
     edition: "2018",
-    rlibs: [
+    rustlibs: [
         "libproc_macro2",
         "libquote",
         "libsyn",