Build bindgen.sh inside android/Android.bp.

* Keep local build modules in android/Android.bp.
* Use cargo2anroid.py to generate ./Android.bp.

Test: make
Change-Id: Ibf60e4397eec50ccc52546fd147df49affecba84
diff --git a/Android.bp b/Android.bp
index c44f133..8f638fb 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,26 +1,4 @@
-// This file is generated by cargo2android.py --run --dependencies --features=clap,runtime,which-rustfmt.
-
-// Add bindgen.sh module and example.
-sh_binary_host {
-    name: "bindgen.sh",
-    src: "android/bindgen.sh",
-}
-
-// Example genrule module to call bindgen.sh:
-//
-// genrule {
-//     name: "my_example",
-//     tools: ["bindgen.sh", "bindgen"],
-//     depfile: true,
-//     srcs: ["src/my_example_wrapper.h"],
-//     out: ["my_example.rs"],
-//     cmd: "$(location)" + my_example_bindgen_flags
-//     + common_bindgen_flags + my_example_clang_flags,
-// }
-//
-// The 'out' file is a rust module to be included into other rust crates.
-
-common_bindgen_flags = " -o $(out) $(in) -- -MD -MF $(depfile)"
+// This file is generated by cargo2android.py --run --dependencies --features=clap,runtime,which-rustfmt --host-first-multilib.
 
 rust_binary_host {
     name: "bindgen",
@@ -51,6 +29,7 @@
         "libshlex",
         "libwhich",
     ],
+    compile_multilib: "first",
 }
 
 rust_library_host {
@@ -81,7 +60,7 @@
         "libshlex",
         "libwhich",
     ],
-    compile_multilib: "first", // added
+    compile_multilib: "first",
 }
 
 // dependent_library ["feature_list"]