Add gn support for regex fuzzer

Allows the tint regex fuzzer to be built using gn, so that it can be
deployed on ClusterFuzz.

Fixes: tint:1075
Change-Id: I88f8bd0eefe3044483b66784cc32feebcdc63928
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/60202
Auto-Submit: Alastair Donaldson <afdx@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Alastair Donaldson <afdx@google.com>

fuzzers/tint_regex_fuzzer/BUILD.gn

@@ -0,0 +1,35 @@
+# Copyright 2021 The Tint Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//build_overrides/build.gni")
+import("../../tint_overrides_with_defaults.gni")
+
+if (build_with_chromium) {
+  source_set("tint_regex_fuzzer") {
+    public_configs = [
+      "${tint_root_dir}/src:tint_config",
+      "${tint_root_dir}/src:tint_common_config",
+    ]
+
+    deps = [ "${tint_root_dir}/fuzzers:tint_fuzzer_common" ]
+
+    sources = [
+      "cli.cc",
+      "cli.h",
+      "fuzzer.cc",
+      "wgsl_mutator.cc",
+      "wgsl_mutator.h",
+    ]
+  }
+}