Add alloc to ciborium-io no_std

This makes the interface for serialization more convenient. (Note that
the main module, ciborium, already has an alloc dependency via half
and serde.)

Bug: 266172411
Test: Builds
(cherry picked from https://android-review.googlesource.com/q/commit:275646277700efc41ab7e914810b53d65fd0e1a7)
Merged-In: Ia684b7dd3a18d6f77a5db02f68f4e1c67046c740
Change-Id: Ia684b7dd3a18d6f77a5db02f68f4e1c67046c740
diff --git a/Android.bp b/Android.bp
index 156a5cc..1610254 100644
--- a/Android.bp
+++ b/Android.bp
@@ -45,9 +45,11 @@
     cargo_pkg_version: "0.2.0",
     srcs: ["src/lib.rs"],
     edition: "2021",
+    features: ["alloc"],
     prefer_rlib: true,
     no_stdlibs: true,
     stdlibs: [
+        "liballoc.rust_sysroot",
         "libcompiler_builtins.rust_sysroot",
         "libcore.rust_sysroot",
     ],
diff --git a/cargo2android_nostd.bp b/cargo2android_nostd.bp
index 6ec59a8..9712ce9 100644
--- a/cargo2android_nostd.bp
+++ b/cargo2android_nostd.bp
@@ -5,9 +5,11 @@
     cargo_pkg_version: "0.2.0",
     srcs: ["src/lib.rs"],
     edition: "2021",
+    features: ["alloc"],
     prefer_rlib: true,
     no_stdlibs: true,
     stdlibs: [
+        "liballoc.rust_sysroot",
         "libcompiler_builtins.rust_sysroot",
         "libcore.rust_sysroot",
     ],