Squashed 'third_party/gflags/' content from commit f0523f1

Change-Id: I7b525481a9f3ec3e48e6656735d06432c25dc3b9
git-subtree-dir: third_party/gflags
git-subtree-split: f0523f14a93cbb46fff9b318508aa1c6923158c7
diff --git a/test/gflags_declare_test.cc b/test/gflags_declare_test.cc
new file mode 100644
index 0000000..707bcc0
--- /dev/null
+++ b/test/gflags_declare_test.cc
@@ -0,0 +1,12 @@
+#include <gflags/gflags.h>
+
+DEFINE_string(message, "", "The message to print");
+void print_message(); // in gflags_declare_flags.cc
+
+int main(int argc, char **argv)
+{
+  gflags::SetUsageMessage("Test compilation and use of gflags_declare.h");
+  gflags::ParseCommandLineFlags(&argc, &argv, true);
+  print_message();
+  return 0;
+}