Yarn: Add GN build files.

src/Vulkan/BUILD.gn

@@ -133,6 +133,7 @@ swiftshader_shared_library("swiftshader_libvulkan") {
     "../Reactor:swiftshader_llvm_reactor",
     "../System",
     "../WSI",
+    "../Yarn",
   ]
 
   include_dirs = [

src/Yarn/BUILD.gn

+# Copyright 2019 The SwiftShader Authors. All Rights Reserved.
+#
+# 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("../swiftshader.gni")
+
+swiftshader_source_set("Yarn") {
+  sources = [
+    "ConditionVariable.hpp",
+    "Containers.hpp",
+    "Debug.cpp",
+    "Debug.hpp",
+    "Defer.hpp",
+    "Finally.hpp",
+    "OSFiber.hpp",
+    "Pool.hpp",
+    "SAL.hpp",
+    "Scheduler.cpp",
+    "Scheduler.hpp",
+    "Thread.cpp",
+    "Thread.hpp",
+    "Ticket.hpp",
+    "Trace.cpp",
+    "Trace.hpp",
+    "Utils.hpp",
+    "WaitGroup.hpp",
+  ]
+
+  if (is_win) {
+    sources += [
+      "OSFiber_windows.hpp",
+    ]
+  } else {
+    sources += [
+      "OSFiber_aarch64.c",
+      "OSFiber_asm_aarch64.h",
+      "OSFiber_asm_aarch64.S",
+      "OSFiber_arm.c",
+      "OSFiber_asm_arm.h",
+      "OSFiber_asm_arm.S",
+      "OSFiber_asm.hpp",
+      "OSFiber_x64.c",
+      "OSFiber_asm_x64.h",
+      "OSFiber_asm_x64.S",
+      "OSFiber_x86.c",
+      "OSFiber_asm_x86.h",
+      "OSFiber_asm_x86.S",
+    ]
+  }
+
+  include_dirs = [
+    "..",
+  ]
+}