bug#35204: 27.0.50; Crash on Cygwin

[Katsumi Yamaoka <yamaoka@jpl.org>]

Hi,

Recently Emacs on Cygwin suddenly crashes while it is (probably)
in idle, only it lives for several minuits, but reverting the
following three changes seems to help.

1. commit 0b8117ed1abfc17bb0bc1690a8997736f1e8f98c
    ; * src/frame.h (MonitorInfo): Remove const modifier
2. commit 7b78857c0ba69eafd780484641b858ae8a167044
    ; * src/xfns.c (x-display-monitor-attributes-list) Fix typo.
3. commit a35e06bbe27c5907f56c5aeb48182d7be00d1dec
    Plug memory leak in GTK x-display-monitor-attributes-list
    * src/frame.c (free_monitors) [USE_GTK]: Define in the GTK case as
      well.
    * src/xfns.c (x-display-monitor-attributes-list) [USE_GTK]: Plug
      memory leak.
    * src/frame.h (MonitorInfo): Declare name as pointing to const char.

I'm not sure what to do but please tell me anything I should do.

In GNU Emacs 27.0.50 (build 3, x86_64-pc-cygwin, GTK+ Version 3.22.28)
 of 2019-04-09 built on localhost
Windowing system distributor 'The Cygwin/X Project', version 11.0.12004000

Configured using:
 'configure CFLAGS=-O0 --verbose --with-x-toolkit=gtk3'

uname -a
CYGWIN_NT-10.0 localhost 3.0.6(0.338/5/3) 2019-04-06 16:18 x86_64 Cygwin


Here is a gdb backtrace I got after reverting only 1.:

(gdb) bt
#0  0x000000010054a66a in terminate_due_to_signal ()
#1  0x000000010057110d in handle_fatal_signal ()
#2  0x00000001005710e0 in deliver_thread_signal ()
#3  0x0000000100571149 in deliver_fatal_thread_signal ()
#4  0x0000000100571361 in handle_sigsegv ()
#5  0x000000018005f65a in altstack_wrapper (sig=<optimized out>, 
    siginfo=<optimized out>, sigctx=0xffffde50, 
    handler=0x1005712a5 <handle_sigsegv>)
    at /usr/src/debug/cygwin-3.0.6-1/winsup/cygwin/exceptions.cc:1595
#6  0x0000000180062dfa in _cygtls::call_signal_handler (this=0xffffce00)
    at /usr/src/debug/cygwin-3.0.6-1/winsup/cygwin/exceptions.cc:1777
#7  0x0000000000000000 in ?? ()

I couldn't fetch a backtrace for Emacs before reverting because
of an error:

(gdb) bt
#0  0x000000010054a72f in terminate_due_to_signal ()
#1  0x000303e90000faf0 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Couldn't fetch xbacktrace either:

(gdb) source .gdbinit
SIGINT is used by the debugger.
Are you sure you want to change it? (y or n) [answered Y; input not from terminal]
DISPLAY = :0.0
TERM = xterm
Breakpoint 1 at 0x10054a66a
.gdbinit:1228: Error in sourced command file:
No symbol "defined_HAVE_X_WINDOWS" in current context.

Thanks.
Regards,