bigger string buffer (https://trac.osgeo.org/grass/ticket/1284; merge from devbr6)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@45907 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.vol.rst/main.c

@@ -210,7 +210,7 @@ int main(int argc, char *argv[])
     int per, npmin;
     int ii, i, n_rows, n_cols, n_levs;
     double x_orig, y_orig, z_orig;
-    char dminchar[10];
+    char dminchar[64];
     struct octdata *data;
     struct octfunc *functions;
     struct octtree *tree;