missing glocale.h header

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@38553 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/cluster/c_exec.c

@@ -12,6 +12,7 @@
 */
 
 #include <grass/cluster.h>
+#include <grass/glocale.h>
 
 /*!
   \param maxclass maximum number of classes