Fix five latent bugs surfaced while porting to WASM

These bugs all exist in stock Magic but were tolerated by the K&R-loose
native build. The strict WASM call_indirect type checks turned them up.

* cif/CIFhier.c: ASSERT in cifFlatMaskHints accessed
  oldproprec->prop_value.prop_type, but prop_type is a top-level member
  of PropertyRecord. Changed to oldproprec->prop_type.

* extflat/EFargs.c: efLoadSearchPath was assigning a pointer to a
  string literal ("." in RO data), which callers later try to free or
  StrDup. Replaced with StrDup(path, ".") so the pointer always lives
  on the heap.

* router/rtrVia.c: rtrFollowName called RtrMilestonePrint("#"), but
  the function takes no arguments.

* sim/SimSelect.c: SimAddLabels called DBWLabelChanged with five
  arguments, but its real signature is (CellDef *, Label *, int).
  Replaced with the equivalent DBWAreaChanged call.

* windows/windView.c: extern declaration of DBMovePoint had return
  type void, but the function actually returns bool.

extflat/EFargs.c

@@ -367,7 +367,7 @@ efLoadSearchPath(path)
     PaVisitFiles(DOT_MAGIC_PATH, ".magicrc", pv);
     PaVisitFree(pv);
     if (*path == NULL)
-	*path = ".";
+	StrDup(path, ".");
 }
 
 int