Enable Local Patches (#2168)

Configure `WORKSPACE` so to use patches that we have in
the current repository

WORKSPACE

@@ -93,8 +93,8 @@ http_archive(
     build_file_content = "# empty",
     patch_args = ["-p1"],
     patches = [
-        "@//:bazel/llvm-patches/0001-Patch-for-mallinfo2-when-using-Bazel-build-system.patch",
-        "@//:bazel/llvm-patches/0002-Added-Bazel-build-for-compiler-rt-fuzzer.patch",
+        "@carbon//bazel/llvm-patches:0001-Patch-for-mallinfo2-when-using-Bazel-build-system.patch",
+        "@carbon//bazel/llvm-patches:0002-Added-Bazel-build-for-compiler-rt-fuzzer.patch",
     ],
     sha256 = "0a3929c5f2fe756820277be7b10e95f7480e7cb7f297ec574d3e9ddeac9068d7",
     strip_prefix = "llvm-project-%s" % llvm_version,

bazel/llvm-patches/BUILD

@@ -0,0 +1,9 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+package(default_visibility = ["//visibility:public"])
+
+exports_files(glob([
+    "*.patch",
+]))