ogsf: change field size to prevent crash

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@57620 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/ogsf/gvld.c

@@ -108,7 +108,7 @@ int gvld_isosurf(geovol * gvl)
     unsigned int *ktrans, *curcolor;
     int pktransp = 0;
 
-    int *pos, *nz, *e_dl, tmp_pos, edge_pos[12];
+    int *pos, *nz, *e_dl, tmp_pos, edge_pos[13];
 
     GLdouble modelMatrix[16], projMatrix[16];
     GLint viewport[4];