[Bazel] Replace uses of deprecated @bazel_tools things

All C++ infrastructure should come from @rules_cc now.

Also the `host_windows` constraint was deprecated a while ago and is
being removed in Bazel 9.

Author: stevenlr

bazel/emscripten_toolchain/toolchain.bzl

@@ -1,8 +1,8 @@
 """This module encapsulates logic to create emscripten_cc_toolchain_config rule."""
 
-load("@bazel_tools//tools/build_defs/cc:action_names.bzl", "ACTION_NAMES")
+load("@rules_cc//cc:action_names.bzl", "ACTION_NAMES")
 load(
-    "@bazel_tools//tools/cpp:cc_toolchain_config_lib.bzl",
+    "@rules_cc//cc:cc_toolchain_config_lib.bzl",
     "action_config",
     "env_entry",
     "env_set",

bazel/remote_emscripten_repository.bzl

@@ -2,6 +2,7 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@rules_cc//cc:defs.bzl", "cc_toolchain", "cc_toolchain_suite")
 load("//emscripten_toolchain:toolchain.bzl", "emscripten_cc_toolchain_config_rule", "emscripten_python_interpreter_files")
 load(":emscripten_build_file.bzl", "EMSCRIPTEN_BUILD_FILE_CONTENT_TEMPLATE")
+load("@platforms//host:constraints.bzl", "HOST_CONSTRAINTS")
 
 def remote_emscripten_repository(
         name,
@@ -55,6 +56,10 @@ def create_toolchains(name, repo_name, exec_compatible_with):
     repo_linker_files_target = remote_repo + ":linker_files"
     repo_ar_files_target = remote_repo + ":ar_files"
 
+    script_extension = "sh"
+    if "@platforms//os:windows" in HOST_CONSTRAINTS:
+        script_extension = "bat"
+
     emscripten_python_interpreter_files(
         name = python_interpreter_name,
     )
@@ -116,10 +121,7 @@ def create_toolchains(name, repo_name, exec_compatible_with):
         em_config = "@emscripten_cache//:emscripten_config",
         emscripten_binaries = repo_compiler_files_target,
         nodejs_bin = "@nodejs//:node",
-        script_extension = select({
-            "@bazel_tools//src/conditions:host_windows": "bat",
-            "//conditions:default": "sh",
-        }),
+        script_extension = script_extension,
     )
 
     cc_toolchain(
@@ -141,7 +143,7 @@ def create_toolchains(name, repo_name, exec_compatible_with):
         target_compatible_with = ["@platforms//cpu:wasm32"],
         exec_compatible_with = exec_compatible_with,
         toolchain = cc_wasm_target,
-        toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+        toolchain_type = "@rules_cc//cc:toolchain_type",
     )
 
     cc_toolchain_suite(