objcopy not properly set in legacy CcToolchainInfo

[quic-sbjorkle]

Tested with rules_cc version 0.1.1 and Bazel 7.4.1 :

When using the new rule_based toolchain pattern overriding the default objcopy tool in cc_tool_map results in the CcToolchainInfo not being properly updated.

Example:

cc_tool_map(
    name = "all_tools",
    tools = {
        "@rules_cc//cc/toolchains/actions:ar_actions": ":ar",
        "@rules_cc//cc/toolchains/actions:assembly_actions": ":gcc",
        "@rules_cc//cc/toolchains/actions:c_compile": ":gcc",
        "@rules_cc//cc/toolchains/actions:cpp_compile_actions": ":g++",
        "@rules_cc//cc/toolchains/actions:link_actions": ":ld",
        "@rules_cc//cc/toolchains/actions:objcopy_embed_data": ":objcopy",
        "@rules_cc//cc/toolchains/actions:strip": ":strip",
    },
    visibility = ["//visibility:public"],
)

cc_tool(
    name = "objcopy",
    src = "@gcc-11.3.0-linux-x86_64//:bin/x86_64-linux-objcopy",
)

-----------------

load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
cc_toolchain = find_cpp_toolchain(ctx)
print(cc_toolchain.objcopy_executable)

Results in cc_toolchain.objcopy_executable to be set to ""

The following workaround could be used until a fix has been implemented:

feature_configuration = cc_common.configure_features(
  ctx = ctx,
  cc_toolchain = cc_toolchain,
  requested_features = [],
  unsupported_features = [],
 )
objcopy_tool_path = cc_common.get_tool_for_action(
  feature_configuration = feature_configuration,
  action_name = "objcopy_embed_data"
)