add zstd.BUILD back

Author: keith

utils/bazel/MODULE.bazel

@@ -15,6 +15,7 @@ bazel_dep(name = "rules_cc", version = "0.2.11")
 bazel_dep(name = "rules_foreign_cc", version = "0.15.1")
 bazel_dep(name = "rules_python", version = "1.6.3")
 bazel_dep(name = "rules_shell", version = "0.6.1")
+bazel_dep(name = "zstd", version = "1.5.7", repo_name = "llvm_zstd")
 
 llvm_repos_extension = use_extension(":extensions.bzl", "llvm_repos_extension")
 use_repo(
@@ -33,8 +34,6 @@ use_repo(
     "vulkan_sdk",
 )
 
-bazel_dep(name = "zstd", version = "1.5.7", repo_name = "llvm_zstd")
-
 llvm_configure = use_repo_rule("@llvm-raw//utils/bazel:configure.bzl", "llvm_configure")
 
 llvm_configure(name = "llvm-project")

utils/bazel/third_party_build/zstd.BUILD

@@ -0,0 +1,55 @@
+# This file is licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
+
+package(
+    default_visibility = ["//visibility:public"],
+    # BSD/MIT-like license (for zstd)
+    licenses = ["notice"],
+)
+
+bool_flag(
+    name = "llvm_enable_zstd",
+    build_setting_default = True,
+)
+
+config_setting(
+    name = "llvm_zstd_enabled",
+    flag_values = {":llvm_enable_zstd": "true"},
+)
+
+cc_library(
+    name = "zstd",
+    srcs = select({
+        ":llvm_zstd_enabled": glob([
+            "lib/common/*.c",
+            "lib/common/*.h",
+            "lib/compress/*.c",
+            "lib/compress/*.h",
+            "lib/decompress/*.c",
+            "lib/decompress/*.h",
+            "lib/decompress/*.S",
+            "lib/dictBuilder/*.c",
+            "lib/dictBuilder/*.h",
+        ]),
+        "//conditions:default": [],
+    }),
+    hdrs = select({
+        ":llvm_zstd_enabled": [
+            "lib/zdict.h",
+            "lib/zstd.h",
+            "lib/zstd_errors.h",
+        ],
+        "//conditions:default": [],
+    }),
+    defines = select({
+        ":llvm_zstd_enabled": [
+            "LLVM_ENABLE_ZSTD=1",
+            "ZSTD_MULTITHREAD",
+        ],
+        "//conditions:default": [],
+    }),
+    strip_include_prefix = "lib",
+)