Enable precompiled headers for spirv-tools(-shared) and some unit tests (#2026)
diff --git a/source/pch_source.cpp b/source/pch_source.cpp
new file mode 100644
index 0000000..032e29e
--- /dev/null
+++ b/source/pch_source.cpp
@@ -0,0 +1,15 @@
+// Copyright (c) 2018 The Khronos Group Inc.
+//
+// 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.
+
+#include "pch_source.h"