* to consrtaint and the communications to variables.
*/
-extern double sg_maxmin_precision;
-extern double sg_surf_precision;
+XBT_EXPORT_NO_IMPORT(double) sg_maxmin_precision;
+XBT_EXPORT_NO_IMPORT(double) sg_surf_precision;
static XBT_INLINE void double_update(double *variable, double value, double precision)
{