Use boost from our source tree

Hopefully this will make master build on robotics.mvla.net again.

Change-Id: Ia7d9dce1aa49dcb909a5dedd5e6bcb673ff66c11
diff --git a/third_party/boostorg/optional/BUILD b/third_party/boostorg/optional/BUILD
new file mode 100644
index 0000000..b355d53
--- /dev/null
+++ b/third_party/boostorg/optional/BUILD
@@ -0,0 +1,15 @@
+licenses(["notice"])  # boost
+
+cc_library(
+    name = "optional",
+    hdrs = glob(["include/**"]),
+    includes = ["include"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//third_party/boostorg/assert",
+        "//third_party/boostorg/core",
+        "//third_party/boostorg/static_assert",
+        "//third_party/boostorg/throw_exception",
+        "//third_party/boostorg/type_traits",
+    ],
+)