Added a function returning maintance version name
diff --git a/lib/constants.cc.in b/lib/constants.cc.in
index d56f45e..e6d5a51 100644
--- a/lib/constants.cc.in
+++ b/lib/constants.cc.in
@@ -59,5 +59,11 @@
   {
     return "@MINOR_VERSION@";
   }
+  
+  const std::string
+  maint_version()
+  {
+    return "@MAINT_VERSION@";
+  }
  } /* namespace gsm */
 } /* namespace gr */