Removes chrono references to make it compile with gcc 4.8.x

src/utils.cc

@@ -196,5 +196,18 @@ void createDir(std::string dir, int mode) {
 #endif
 }
 
+
+double cpu_seconds(void) {
+        struct timespec t;
+
+        if (!clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &t))
+                return static_cast<double>(t.tv_sec)
+                     + static_cast<double>(t.tv_nsec / 1000000000.0);
+        else
+                return static_cast<double>(clock()) /
+                    static_cast<double>(CLOCKS_PER_SEC);
+}
+
+
 }  // namespace ModSecurity