Add AArch64 device Rust toolchain.

Bug: 141207434
Test: build example rust device module.
Change-Id: I0932a614942bf4a4d4b6c153fcc4fc79c7f202bd

rust/binary.go

@@ -71,6 +71,15 @@ func (binary *binaryDecorator) preferDynamic() bool {
 
 func (binary *binaryDecorator) compilerFlags(ctx ModuleContext, flags Flags) Flags {
 	flags = binary.baseCompiler.compilerFlags(ctx, flags)
+
+	if ctx.toolchain().Bionic() {
+		// no-undefined-version breaks dylib compilation since __rust_*alloc* functions aren't defined, but we can apply this to binaries.
+		flags.LinkFlags = append(flags.LinkFlags,
+			"-Wl,--gc-sections",
+			"-Wl,-z,nocopyreloc",
+			"-Wl,--no-undefined-version")
+	}
+
 	if binary.preferDynamic() {
 		flags.RustFlags = append(flags.RustFlags, "-C prefer-dynamic")
 	}
@@ -86,6 +95,12 @@ func (binary *binaryDecorator) compilerDeps(ctx DepsContext, deps Deps) Deps {
 		}
 	}
 
+	if ctx.toolchain().Bionic() {
+		deps = binary.baseCompiler.bionicDeps(ctx, deps)
+		deps.CrtBegin = "crtbegin_dynamic"
+		deps.CrtEnd = "crtend_android"
+	}
+
 	return deps
 }