versioner: introduce.

Add a clang-based tool to inspect header availability attributes and
verify them against the NDK platform definitions.

Bug: http://b/28178111
Change-Id: I1bb1925a620e98cc9606cb5a3360b1224c700bd0
diff --git a/tools/versioner/src/Utils.h b/tools/versioner/src/Utils.h
new file mode 100644
index 0000000..f4845b8
--- /dev/null
+++ b/tools/versioner/src/Utils.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2016 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+std::string getWorkingDir();
+std::vector<std::string> collectFiles(const std::string& directory);
+
+namespace std {
+static __attribute__((unused)) std::string to_string(const char* c) {
+  return c;
+}
+
+static __attribute__((unused)) const std::string& to_string(const std::string& str) {
+  return str;
+}
+}
+
+template <typename Collection>
+static std::string Join(Collection c, const std::string& delimiter = ", ") {
+  std::string result;
+  for (const auto& item : c) {
+    result.append(std::to_string(item));
+    result.append(delimiter);
+  }
+  if (!result.empty()) {
+    result.resize(result.length() - delimiter.length());
+  }
+  return result;
+}