Add first benchmark

Summary: Implement some very basic benchmarking infra. We need benchmarks in css-layout and I want to add something now so that others have the option to follow an example when implementing a benchmark.

Reviewed By: lucasr

Differential Revision: D3648889

fbshipit-source-id: 60b93c6e5ed027a37195a9a5d86e681e3e79a5b9

BUCK

@@ -33,6 +33,18 @@ cxx_library(
   visibility = ['PUBLIC'],
 )
 
+cxx_binary(
+  name = 'benchmark',
+  srcs = glob(['benchmarks/*.c']),
+  headers = subdir_glob([('', 'benchmarks/*.h')]),
+  header_namespace = '',
+  compiler_flags = COMPILER_FLAGS,
+  deps = [
+    ':CSSLayout',
+  ],
+  visibility = ['PUBLIC'],
+)
+
 cxx_library(
   name = 'CSSLayoutTestUtils',
   srcs = glob(['tests/CSSLayoutTestUtils/*.c']),