Added `bzl_srcs` targets which only contain `.bzl` files for use in stardoc

cc/BUILD

@@ -45,6 +45,17 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 
+filegroup(
+    name = "bzl_srcs",
+    srcs = glob([
+        "**/*.bzl",
+    ]) + [
+        "//cc/private/rules_impl:bzl_srcs",
+        "//cc/private/toolchain:bzl_srcs",
+    ],
+    visibility = ["//visibility:public"],
+)
+
 filegroup(
     name = "srcs",
     srcs = glob([

cc/private/rules_impl/BUILD

@@ -2,6 +2,13 @@ package(default_visibility = ["//visibility:public"])
 
 licenses(["notice"])  # Apache 2.0
 
+filegroup(
+    name = "bzl_srcs",
+    srcs = glob([
+        "**/*.bzl",
+    ]),
+)
+
 filegroup(
     name = "srcs",
     srcs = glob([

cc/private/toolchain/BUILD

@@ -65,6 +65,11 @@ filegroup(
     srcs = [],
 )
 
+filegroup(
+    name = "bzl_srcs",
+    srcs = glob(["**/*.bzl"]),
+)
+
 filegroup(
     name = "srcs",
     srcs = glob(["**"]),

tools/migration/BUILD

@@ -132,7 +132,10 @@ filegroup(
     ],
 )
 
-exports_files(["ctoolchain_compare.bzl"])
+exports_files([
+    "cc_toolchain_config_comparator.bzl",
+    "ctoolchain_compare.bzl",
+])
 
 bzl_library(
     name = "ctoolchain_compare_bzl",