Move timespec2seconds to utils

src/utils.h

@@ -291,6 +291,16 @@ namespace LAMMPS_NS {
      * \return conversion factor
      */
     double get_conversion_factor(const int property, const int conversion);
+
+// convert a timespec ([[HH:]MM:]SS) to seconds
+
+    /**
+     * \brief Convert a time string to seconds
+     *        The strings "off" and "unlimited" result in -1
+     * \param timespec a string in the following format: ([[HH:]MM:]SS)
+     * \return total in seconds
+     */
+    double timespec2seconds(const std::string & timespec);
   }
 }