slow make-frame + face initialization / importing x resources

[David Reitter <david.reitter@gmail.com>]

I wonder if something can be done about the very slow `make-frame'.

Make-frame creates a frame-local copy of each face defined, and when  
you have a couple of faces defined for various modes, just a modest  
number of them (I have 700, defined with color-theme) will slow down  
frame creation to a point where it's just not tolerable any more.

Here's a bit of code to demonstrate the effect (with just "empty'  
faces):

(require 'cl)
(loop for X from 0 to 2000 do
       (make-face (intern (format "face%s" X))))
(let ((ti (current-time)))
   (loop for X from 0 to 10 do
	(make-frame))
   (print (format-time-string "%S" (time-since ti))))

The problem seems to be due to `x-create-frame-with-faces',  
specifically this form:

(dolist (face (delq 'default (face-list)))
       (condition-case ()
	  (progn
	    (face-spec-set face (face-user-default-spec face) frame)
	    (if (memq window-system '(x w32 mac))
		(make-face-x-resource-internal face frame))
	    (internal-merge-in-global-face face frame))
	(error nil)))

Frame creation time improves tremendously when I take out that call  
to `make-face-x-resource-internal'.
Is the import of x-resources necessary on Mac and Windows?
Also, is it necessary to do that every time a frame is created?  
Couldn't they be imported once at startup time?