bug#25851: 25.2; GTK warning when starting Emacs when desktop file has more than one frame

[Eli Zaretskii <eliz@gnu.org>]

> From: nljlistbox2@gmail.com (N. Jackson)
> Cc: 25851@debbugs.gnu.org
> Date: Fri, 24 Feb 2017 11:09:22 -0500
> 
> This is my interaction with GDB after `C-x 5 2':
> 
>   Thread 1 "emacs" hit Breakpoint 3, xg_set_geometry (f=0x386d000) at gtkutil.c:778
>   778       if (f->size_hint_flags & (USPosition | PPosition))
>   (gdb) print f->size_hint_flags 
>   $3 = 0

If the value of the hint flags is zero, none of the individual hints
will match, obviously.

>   (gdb) print USPosition
>   No symbol "USPosition" in current context.
>   (gdb) print PPosition
>   No symbol "PPosition" in current context.
>   (gdb) print (USPosition | PPosition)
>   No symbol "USPosition" in current context.
>   (gdb) print (f->size_hint_flags & (USPosition | PPosition))
>   No symbol "USPosition" in current context.
>   (gdb) n
>   808     }
>   (gdb)
> 
> Is my syntax wrong when I try to get the values?

It sometimes happens with preprocessor macros.  The trick I use in
those cases is this:

  (gdb) print USPosition+0

If even this doesn't help, it most probably means Emacs wasn't
compiled with the -g3 flag.

In any case, googling finds this:

  https://tronche.com/gui/x/xlib/ICC/client-to-window-manager/wm-normal-hints.html

which shows the values of the flags.