Merge changes from topic "add_rust_arm64_devices"

* changes:
  Add ARM32 device Rust toolchain.
  Add AArch64 device Rust toolchain.

cc/cc.go

@@ -401,6 +401,14 @@ func StaticDepTag() dependencyTag {
 	return staticDepTag
 }
 
+func CrtBeginDepTag() dependencyTag {
+	return crtBeginDepTag
+}
+
+func CrtEndDepTag() dependencyTag {
+	return crtEndDepTag
+}
+
 // Module contains the properties and members used by all C/C++ module types, and implements
 // the blueprint.Module interface.  It delegates to compiler, linker, and installer interfaces
 // to construct the output file.  Behavior can be customized with a Customizer interface