third_party: Add build file for optional (#16)

Author: jungleraptor

third_party/optional.BUILD

@@ -0,0 +1,19 @@
+# Copyright (C) 2022 Swift Navigation Inc.
+# Contact: Swift Navigation <[email protected]>
+#
+# This source is subject to the license found in the file 'LICENSE' which must
+# be be distributed together with this source. All other rights reserved.
+#
+# THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
+# EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "optional",
+    hdrs = ["optional.hpp"],
+    includes = ["."],
+)