Add missing version source file

src/anbox/build/version.cpp

+/*
+ * Copyright (C) 2017 Simon Fels <morphis@gravedo.de>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "anbox/build/version.h"
+#include "anbox/utils.h"
+
+namespace anbox {
+namespace build {
+std::string print_version() {
+  static std::string v;
+  if (v.empty()) {
+    if (version_suffix.empty())
+      v = utils::string_format("%d", version_major);
+    else
+      v = utils::string_format("%d-%s", version_major, version_suffix);
+  }
+  return v;
+}
+}  // namespace build
+}  // namespace anbox