compiler warning

polygon/GenericPolygonClipperLibrary.cpp

@@ -1788,7 +1788,7 @@ void gpc_tristrip_clip(gpc_op op, gpc_polygon *subj, gpc_polygon *clip,
   polygon_node  *tlist= NULL, *tn, *tnn, *p, *q;
   vertex_node   *lt, *ltn, *rt, *rtn;
   h_state        horiz[2];
-  vertex_type    cft;
+  vertex_type    cft = vertex_type(-1);
   int            in[2], exists[2], parity[2]= {LEFT, LEFT};
   int            s, v, contributing, search, scanbeam= 0, sbt_entries= 0;
   int            vclass, bl, br, tl, tr;