Added BUILD.gn

Change-Id: Ib0d0ccf9cabd77cf85fae90f4237cf2428347bc2
diff --git a/BUILD.gn b/BUILD.gn
new file mode 100644
index 0000000..81e102e
--- /dev/null
+++ b/BUILD.gn
@@ -0,0 +1,40 @@
+# Copyright 2016 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+config("expat_config") {
+  include_dirs = [
+    "expat/lib",
+    "expat/vms",
+  ]
+  defines = [ "HAVE_EXPAT_CONFIG_H" ]
+}
+
+source_set("expat") {
+  public_configs = [ ":expat_config" ]
+  public = [
+    "expat/lib/expat.h",
+  ]
+  sources = [
+    "expat/lib/amigaconfig.h",
+    "expat/lib/ascii.h",
+    "expat/lib/asciitab.h",
+    "expat/lib/expat_external.h",
+    "expat/lib/iasciitab.h",
+    "expat/lib/internal.h",
+    "expat/lib/latin1tab.h",
+    "expat/lib/macconfig.h",
+    "expat/lib/nametab.h",
+    "expat/lib/utf8tab.h",
+    "expat/lib/watcomconfig.h",
+    "expat/lib/winconfig.h",
+    "expat/lib/xmlparse.c",
+    "expat/lib/xmlrole.c",
+    "expat/lib/xmlrole.h",
+    "expat/lib/xmltok.c",
+    "expat/lib/xmltok.h",
+    "expat/lib/xmltok_impl.c",
+    "expat/lib/xmltok_impl.h",
+    "expat/lib/xmltok_ns.c",
+  ]
+}