"save as" no longer sends an initial file name to the tk_getSaveFile

function - this seems to have stopped working in tcl 8.5 on Macintosh (the
initialfile gets incorporated into the initialdir and the dialog gets badly
confused.)  Workaround is simply not to supply it.

tcl/pdtk_canvas.tcl

@@ -126,7 +126,7 @@ proc pdtk_canvas_raise {mytoplevel} {
 
 proc pdtk_canvas_saveas {name initialfile initialdir destroyflag} {
     if { ! [file isdirectory $initialdir]} {set initialdir $::filenewdir}
-    set filename [tk_getSaveFile -initialfile $initialfile -initialdir $initialdir \
+    set filename [tk_getSaveFile -initialdir $initialdir \
                       -defaultextension .pd -filetypes $::filetypes]
     if {$filename eq ""} return; # they clicked cancel