Mark extension as reproducible (#570)

Avoids an unnecessary lockfile entry.

Author: fmeum

MODULE.bazel

@@ -19,6 +19,7 @@ module(
     compatibility_level = 0,
 )
 
+bazel_dep(name = "bazel_features", version = "1.36.0")
 bazel_dep(name = "bazel_skylib", version = "1.5.0")
 bazel_dep(name = "rules_cc", version = "0.2.2")
 bazel_dep(name = "platforms", version = "0.0.8")

toolchain/extensions/llvm.bzl

@@ -1,5 +1,6 @@
 """LLVM extension for use with bzlmod"""
 
+load("@bazel_features//:features.bzl", "bazel_features")
 load("@toolchains_llvm//toolchain:rules.bzl", "llvm_toolchain")
 load(
     "@toolchains_llvm//toolchain/internal:repo.bzl",
@@ -84,6 +85,11 @@ def _llvm_impl_(module_ctx):
             if root.name not in toolchain_names:
                 fail("sysroot '%s' does not have a corresponding toolchain" % root.name)
 
+    if bazel_features.external_deps.extension_metadata_has_reproducible:
+        return module_ctx.extension_metadata(reproducible = True)
+    else:
+        return None
+
 _attrs = {
     "name": attr.string(doc = """\
         Base name for the generated repositories, allowing more than one LLVM toolchain to be registered.