Derive runtime search dirs from foreign cc deps

[jsun-splunk]

Foreign-built binaries and shared libraries can depend on shared libraries from deps or dynamic_deps. Some upstream builds also install companion shared libraries under out_bin_dir and out_lib_dir without runtime search paths between those outputs. Add opt-in derivation so foreign_cc outputs can resolve dependency libraries and, when requested, companion libraries from the same foreign build without loader environment variables such as LD_LIBRARY_PATH.

Public attrs:

• runtime_library_search_directories
• include_self_runtime_library_search_directories
• runtime_library_search_mode
• additional_dynamic_runtime_library_search_origins
• additional_executable_runtime_library_search_origins

runtime_library_search_directories accepts:

• auto: follow
  @rules_foreign_cc//foreign_cc/settings:runtime_library_search_directories
• enabled: force runtime search directory derivation on for this target
• disabled: force runtime search directory derivation off for this target

The global build setting defaults to disabled, so the default behavior remains disabled unless a target opts in or the build setting is enabled.

configure_make(
    name = "python",
    out_binaries = ["python3.10"],
    out_shared_libs = ["libpython3.10.so"],
    out_data_dirs = ["lib"],
    runtime_library_search_directories = "enabled",
    additional_dynamic_runtime_library_search_origins = [
        "lib/python3.10/lib-dynload",
    ],
)

configure_make(
    name = "openssl",
    out_shared_libs = ["libssl.so", "libcrypto.so"],
    runtime_library_search_directories = "enabled",
    include_self_runtime_library_search_directories = True,
)

make(
    name = "runtime_app",
    out_binaries = ["runtime_app"],
    runtime_library_search_directories = "auto",
    runtime_library_search_mode = "executable",
    executable_ldflags_vars = ["LDFLAGS"],
    deps = [":runtime_lib"],
)

cmake(
    name = "runtime_lib",
    out_shared_libs = ["libruntime.so"],
    runtime_library_search_directories = "enabled",
    runtime_library_search_mode = "shared",
    deps = [":leaf_lib"],
)

Default origins are derived from declared output File.short_path values. Shared-library link actions use the directories of declared shared-library outputs. Executable link actions use the directories of declared binary outputs. Additional origins are install-tree-relative paths joined under the rule install root.

The implementation passes a runtime_search_context from the common framework into linker flag derivation. It uses declared output files for default origins, the framework install root for additional origins, and LibraryToLink short paths for dependency shared libraries. It also adds _solib sibling paths for Bazel-created solib symlinks and skips runtime search derivation for Windows C++ toolchains.

Supported exported rules are cmake, make, and configure_make. ninja and meson inherit the attrs as best-effort support. boost_build does not expose them because its b2 interface does not map cleanly onto the common linker flag plumbing used here.

Unit tests cover mode filtering, default origins, additional origins, self-output search paths, _solib paths, deduplication, and auto resolution through the global build setting. Example integration tests build app -> libmiddle.so -> libleaf.so chains with cmake, make, and configure_make.

This PR depends on #1538