Build oak_restricted_kernel_wrapper for bare metal with Bazel.

Also set up bare metal toolchain to not link in libc - note "link-arg=-nostdlib"

BUG: 349587445
BUG: 352536995
Change-Id: I9023c7f3b55d4d535bdc3b1e54230bd8de09b157

WORKSPACE

@@ -303,6 +303,7 @@ gcc_register_toolchain(
 
 gcc_register_toolchain(
     name = "gcc_toolchain_x86_64_unknown_none",  # Repository @gcc_toolchain_x86_64_unknown_none
+    extra_ldflags = ["-nostdlib"],
     target_arch = ARCHS.x86_64,
     target_compatible_with = [
         "@platforms//cpu:x86_64",

oak_restricted_kernel_wrapper/BUILD

@@ -0,0 +1,41 @@
+#
+# Copyright 2024 The Project Oak Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+load("@rules_rust//rust:defs.bzl", "rust_binary")
+
+package(
+    default_visibility = ["//visibility:public"],
+    licenses = ["notice"],
+)
+
+rust_binary(
+    name = "oak_restricted_kernel_wrapper",
+    srcs = glob(["src/**/*.rs"]),
+    compile_data = ["src/asm/boot.s"],
+    crate_features = ["bazel"],  # TODO: b/333064338 remove.
+    data = [
+        "//oak_restricted_kernel_bin:oak_restricted_kernel_bin_virtio_console_channel",
+    ],
+    platform = "//:x86_64-unknown-none",
+    rustc_env = {
+        "PAYLOAD_PATH": "$(location //oak_restricted_kernel_bin:oak_restricted_kernel_bin_virtio_console_channel)",
+    },
+    deps = [
+        "@//oak_linux_boot_params",
+        "@oak_no_std_crates_index//:elf",
+        "@oak_no_std_crates_index//:x86_64",
+    ],
+)