use prebuilt protoc to avoid setup of a CC toolchain

.bazelrc

@@ -2,3 +2,6 @@
 # `bazel run @rules_bazel_integration_test//tools:update_deleted_packages`
 build --deleted_packages=examples/full,examples/full/tool_test
 query --deleted_packages=examples/full,examples/full/tool_test
+
+# for stardoc
+common --incompatible_enable_proto_toolchain_resolution

MODULE.bazel

@@ -4,19 +4,59 @@ module(
     compatibility_level = 0,
 )
 
+# ✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂
+# only dev_dependencies below this line - rules_gcs is lean
+# ✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂✂
+
 bazel_dep(
     name = "bazel_skylib",
     version = "1.7.1",
     dev_dependency = True,
 )
+bazel_dep(
+    name = "rules_bazel_integration_test",
+    version = "0.25.0",
+    dev_dependency = True,
+)
+bazel_dep(
+    name = "rules_java",
+    version = "7.4.0",
+    dev_dependency = True,
+)
+bazel_dep(
+    name = "rules_proto",
+    version = "6.0.2",
+    dev_dependency = True,
+)
 bazel_dep(
     name = "stardoc",
     version = "0.7.0",
     dev_dependency = True,
 )
 bazel_dep(
-    name = "rules_bazel_integration_test",
-    version = "0.25.0",
+    name = "toolchains_protoc",
+    version = "0.3.2",
+    dev_dependency = True,
+)
+
+protoc = use_extension("@toolchains_protoc//protoc:extensions.bzl", "protoc")
+protoc.toolchain(
+    # Creates a repository to satisfy well-known-types dependencies such as
+    # deps=["@com_google_protobuf//:any_proto"]
+    google_protobuf = "com_google_protobuf",
+    version = "v27.0",
+)
+
+http_jar = use_repo_rule("@bazel_tools//tools/build_defs/repo:http.bzl", "http_jar")
+
+http_jar(
+    name = "protobuf-java",
+    sha256 = "9072e60fe66cff5d6c0f11a1df21d8f3e4b29b5ee782b45c3fc75f59fbe2b839",
+    urls = ["https://repo1.maven.org/maven2/com/google/protobuf/protobuf-java/4.27.0/protobuf-java-4.27.0.jar"],
+)
+
+register_toolchains(
+    "//docs/lang_toolchains:all",
     dev_dependency = True,
 )
 

docs/lang_toolchains/BUILD.bazel

@@ -0,0 +1,9 @@
+load("@rules_proto//proto:defs.bzl", "proto_lang_toolchain")
+
+proto_lang_toolchain(
+    name = "protoc_java_toolchain",
+    command_line = "--java_out=%s",
+    progress_message = "Generating Java proto_library %{label}",
+    runtime = "@protobuf-java//jar",
+    toolchain_type = "@rules_java//java/proto:toolchain_type",
+)