r.watershed: reduce chance of integer overflow

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@71614 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.watershed/seg/init_vars.c

@@ -430,7 +430,7 @@ int init_vars(int argc, char *argv[])
 
     G_debug(1, "open segments for A* points");
     /* columns per segment */
-    seg_cols = seg_rows * seg_rows;
+    seg_cols = seg_rows * 200; /* check for integer overflow ? */
     num_cseg_total = do_points / seg_cols;
     if (do_points % seg_cols > 0)
 	num_cseg_total++;
@@ -449,7 +449,7 @@ int init_vars(int argc, char *argv[])
     G_debug(1, "heap memory %.2f MB", heap_mem);
     /* columns per segment */
     /* larger is faster */
-    seg_cols = seg_rows * seg_rows;
+    seg_cols = seg_rows * 300; /* check for integer overflow ? */
     num_cseg_total = do_points / seg_cols;
     if (do_points % seg_cols > 0)
 	num_cseg_total++;