Bug #1138: Wrap funcs in CW's GC ops as well. While this is unnecessary

according to the rules as I understand them (bug #1045), not everybody
    follows the rules. GC funcs were being called on the same GC from
    within GC ops, and the cwValidateGC caused a loop in the funcs chain
    that resulted in a crash, notably in cwPolylines.

miext/cw/cw.c

@@ -65,7 +65,7 @@ cwCopyClip(GCPtr pgcDst, GCPtr pgcSrc);
 static void
 cwDestroyClip(GCPtr pGC);
 
-static GCFuncs cwGCFuncs = {
+GCFuncs cwGCFuncs = {
     cwValidateGC,
     cwChangeGC,
     cwCopyGC,

miext/cw/cw_ops.c

@@ -37,14 +37,19 @@
 	&src_off_y)
 
 #define PROLOGUE(pGC) do { \
+    pGC->funcs = pGCPrivate->wrapFuncs;\
     pGC->ops = pGCPrivate->wrapOps;\
 } while (0)
 
 #define EPILOGUE(pGC) do { \
+    pGCPrivate->wrapFuncs = (pGC)->funcs; \
     pGCPrivate->wrapOps = (pGC)->ops; \
+    (pGC)->funcs = &cwGCFuncs; \
     (pGC)->ops = &cwGCOps; \
 } while (0)
 
+extern GCFuncs cwGCFuncs;
+
 /*
  * GC ops -- wrap each GC operation with our own function
  */