bug#17526: 24.3.90; Crash in Cygwin-w32 build

[Eli Zaretskii]

> Date: Mon, 19 May 2014 08:30:49 -0400
> From: Ken Brown <kbrown@cornell.edu>
> 
> I just got a crash with the following backtrace:
> 
> #0  0x000007fefd5f3ca3 in KERNELBASE!DebugBreak ()
>    from /c/Windows/system32/KERNELBASE.dll
> #1  0x000000010061a344 in emacs_abort ()
>     at /usr/src/debug/emacs-24.3.90-1/src/w32fns.c:8460
> #2  0x000000010043616a in move_it_to (it=0x4284e0, to_charpos=-1, to_x=-1,
>     to_y=-1, to_vpos=10, op=4)
>     at /usr/src/debug/emacs-24.3.90-1/src/xdisp.c:9198
> #3  0x0000000100436fc2 in move_it_by_lines (it=0x4284e0, dvpos=10)
>     at /usr/src/debug/emacs-24.3.90-1/src/xdisp.c:9490
> #4  0x000000010048972d in window_scroll_pixel_based (window=4312108109, n=10,
>     whole=false, noerror=0) at 
> /usr/src/debug/emacs-24.3.90-1/src/window.c:5021
> #5  0x0000000100488e6e in window_scroll (window=4312108109, n=10, whole=false,
>     noerror=0) at /usr/src/debug/emacs-24.3.90-1/src/window.c:4838
> #6  0x000000010048a976 in scroll_command (n=40, direction=1)
>     at /usr/src/debug/emacs-24.3.90-1/src/window.c:5395
> #7  0x000000010048a9ad in Fscroll_up (arg=40)
>     at /usr/src/debug/emacs-24.3.90-1/src/window.c:5410

I merged this with #17539, since they seem to be the same bug.