Adding Google benchmarking library.

third_party/google_benchmark/cmake/posix_regex.cpp

Index: third_party/google_benchmark/cmake/posix_regex.cpp
diff --git a/third_party/google_benchmark/cmake/posix_regex.cpp b/third_party/google_benchmark/cmake/posix_regex.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..466dc62560a27d003b9dd083f0a356b44a4fb83f
--- /dev/null
+++ b/third_party/google_benchmark/cmake/posix_regex.cpp
@@ -0,0 +1,14 @@
+#include <regex.h>
+#include <string>
+int main() {
+  std::string str = "test0159";
+  regex_t re;
+  int ec = regcomp(&re, "^[a-z]+[0-9]+$", REG_EXTENDED | REG_NOSUB);
+  if (ec != 0) {
+    return ec;
+  }
+  int ret = regexec(&re, str.c_str(), 0, nullptr, 0) ? -1 : 0;
+  regfree(&re);
+  return ret;
+}
+