emacs xfont.c doing XINT(nil)

[Ken Raeburn]

In xfont.c around line 400 or so, font_parse_xlfd is called without  
checking its return value.  On Mac OS X, building for X11, I'm seeing  
font_parse_xlfd get passed "7x14" and return -1, indicating that it  
hasn't filled in the fields of "entity".  So a few lines further down,  
when checking for scalable fonts, XINT is applied to a couple of array  
elements that are actually nil.

I'm working on some changes which, among other things, really want  
XINT/XUINT to only get applied to Lisp objects that represent  
integers, so I noticed.  Otherwise, I haven't noticed any problems...  
but I don't know what I would be looking for anyways, as I don't do  
much with fonts in Emacs.  I do have "Emacs*font: 7x14" set in my X  
resources though, from long ago.

With some printf instrumentation, I'm seeing these calls being mode  
(and showing the count and names returned by XListFonts):

xfont_list_pattern(-*-7x14-*-*-*-*-*-*-*-*-*-*-iso8859-1) -> 0 matches
xfont_list_pattern(7x14) -> 1 matches
 font #  0 = '7x14'
 font_parse_xlfd returns -1
xfont_list_pattern(-*-7x14-*-*-*-*-*-*-*-*-*-*-ascii-0) -> 0 matches
xfont_list_pattern(7x14) -> 1 matches
 font #  0 = '7x14'
 font_parse_xlfd returns -1
font_list_pattern(-misc-fixed-*-*-*--*-*-*-*-*-*-iso8859-1) -> 53  
matches
[...everything looks happy...]
xfont_list_pattern(-misc-fixed-*-*-*--*-*-*-*-c-*-iso8859-1) -> 53  
matches
[...everything looks happy...]

I'm not sure what the right behavior should be here, if  
font_parse_xlfd fails.  The current behavior appears to be that the  
font is not added to the list being generated.  With "entity" not  
getting filled in when the name isn't in the expected form, that's  
probably the right behavior at the lower level, but should the code be  
doing something else to get a useable name?

Ken