fix: update build_test() fork for compatibility with Bazel 8.3.0

We here imitate the changes in bazel_skylib 1.8.1 to avoid referring
to `@bazel_tools//src/conditions:host_windows`.  As of Bazel 8.3.0
referring to `@bazel_tools//src/conditions:host_windows` yields a
deprecation warning.

In concert with this, we go ahead and bump the minimum required
version of bazel_skylib to 1.8.1.

Fixes #824

Author: dws

MODULE.bazel

@@ -9,7 +9,7 @@ module(
 # Lower-bounds (minimum) versions for direct runtime dependencies
 bazel_dep(name = "aspect_bazel_lib", version = "2.9.3")
 bazel_dep(name = "aspect_rules_js", version = "2.0.0")
-bazel_dep(name = "bazel_skylib", version = "1.5.0")
+bazel_dep(name = "bazel_skylib", version = "1.8.1")
 bazel_dep(name = "platforms", version = "0.0.5")
 
 # TODO(4.x): remove support for non-toolchainized protoc

ts/private/build_test.bzl

@@ -11,10 +11,11 @@ It is used to force Bazel to build some of its dependencies, in the case where
 """
 
 def _build_test_impl(ctx):
-    # See https://github.com/bazelbuild/bazel-skylib/blob/1.7.1/rules/build_test.bzl#L19-L33
+    # See https://github.com/bazelbuild/bazel-skylib/blob/1.8.0/rules/build_test.bzl#L19-L34
 
-    extension = ".bat" if ctx.attr.is_windows else ".sh"
-    content = "exit 0" if ctx.attr.is_windows else "#!/usr/bin/env bash\nexit 0"
+    is_windows = ctx.target_platform_has_constraint(ctx.attr._windows_constraint[platform_common.ConstraintValueInfo])
+    extension = ".bat" if is_windows else ".sh"
+    content = "exit 0" if is_windows else "#!/usr/bin/env bash\nexit 0"
     executable = ctx.actions.declare_file(ctx.label.name + extension)
     ctx.actions.write(
         output = executable,
@@ -34,17 +35,13 @@ _build_test = rule(
     implementation = _build_test_impl,
     attrs = {
         "targets": attr.label_list(allow_files = True),
-        "is_windows": attr.bool(mandatory = True),
+        "_windows_constraint": attr.label(default = "@platforms//os:windows"),
     },
     test = True,
 )
 
 def build_test(name, **kwargs):
     _build_test(
         name = name,
-        is_windows = select({
-            "@bazel_tools//src/conditions:host_windows": True,
-            "//conditions:default": False,
-        }),
         **kwargs
     )

ts/repositories.bzl

@@ -24,8 +24,8 @@ def http_archive(**kwargs):
 def rules_ts_bazel_dependencies():
     http_archive(
         name = "bazel_skylib",
-        sha256 = "cd55a062e763b9349921f0f5db8c3933288dc8ba4f76dd9416aac68acee3cb94",
-        urls = ["https://github.com/bazelbuild/bazel-skylib/releases/download/1.5.0/bazel-skylib-1.5.0.tar.gz"],
+        sha256 = "51b5105a760b353773f904d2bbc5e664d0987fbaf22265164de65d43e910d8ac",
+        urls = ["https://github.com/bazelbuild/bazel-skylib/releases/download/1.8.1/bazel-skylib-1.8.1.tar.gz"],
     )
 
     http_archive(