Copy over runfiles library from Bazel

The runfiles library can be maintained independently of Bazel releases and bazel_tools can refer to it via an alias.

.gitignore

@@ -1,2 +1,4 @@
 bazel-*
 MODULE.bazel.lock
+/.ijwb/
+/.clwb/

MODULE.bazel

@@ -13,5 +13,6 @@ use_repo(cc_configure, "local_config_cc", "local_config_cc_toolchains")
 
 register_toolchains("@local_config_cc_toolchains//:all")
 
+bazel_dep(name = "googletest", version = "1.15.2", dev_dependency = True)
 bazel_dep(name = "rules_testing", version = "0.6.0", dev_dependency = True)
 bazel_dep(name = "stardoc", version = "0.7.0", dev_dependency = True)

WORKSPACE

@@ -30,3 +30,10 @@ http_archive(
     strip_prefix = "rules_testing-0.6.0",
     url = "https://github.com/bazelbuild/rules_testing/releases/download/v0.6.0/rules_testing-v0.6.0.tar.gz",
 )
+
+http_archive(
+    name = "googletest",
+    integrity = "sha256-e0K01u1IgQxTYsJloX+uvpDcI3PIheUhZDnTeSfwKSY=",
+    strip_prefix = "googletest-1.15.2",
+    url = "https://github.com/google/googletest/releases/download/v1.15.2/googletest-1.15.2.tar.gz",
+)

cc/runfiles/BUILD

@@ -1,7 +1,14 @@
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
+
 licenses(["notice"])
 
-alias(
+cc_library(
     name = "runfiles",
-    actual = "@bazel_tools//tools/cpp/runfiles",
+    srcs = ["runfiles.cc"],
+    hdrs = ["runfiles.h"],
+    # Ensure that this header can be included from the same directory as the
+    # legacy @bazel_tools//tools/cpp/runfiles library.
+    include_prefix = "tools/cpp/runfiles",
+    strip_include_prefix = ".",
     visibility = ["//visibility:public"],
 )