[9fans] font cache resize failed

[9fans] font cache resize failed

[erik quanstrom]

i've been having on-and-off trouble with page and proof issuing
this error "font cache resized failed: out of memory".  it turned
out that fontresize() was being called with wid=0 from loadchar.
evidently this is not a problem with my font, as proof sometimes
does this even when displaying no menu.  

i temporarly solved this problem with this hack:

9diff font.c
/n/sources/plan9//sys/src/libdraw/font.c:359,368 - font.c:359,369
  	d = f->display;
  	if(d == nil)
  		goto Nodisplay;
- 
+ 	if(wid == 0)
+ 		wid = 1;		// hack?
  	new = allocimage(d, Rect(0, 0, ncache*wid, f->height), CHAN1(CGrey, depth), 0, 0);

i'm not sure if this is a terrible hack or not.  it's not
if zero-width characters could sometimes be expected.

- erik