On Thu, 11 Apr 2019 16:19:28 +0300, Eli Zaretskii wrote:
>> (gdb) source .gdbinit
[...]
>> .gdbinit:1228: Error in sourced command file:
>> No symbol "defined_HAVE_X_WINDOWS" in current context.

> This is why I suggested to use CFLAGS='-O0 -g3', please try that next.

I did so.

[...]
> This is still not the information we need.  Since "thread apply all"
> crashes, please try this alternative:

>   (gdb) thread 1
>   (gdb) bt

The result is in the first attachment, and

> And please separately do also this:

>   (gdb) info threads

that of it is in the second attachment.

> and post the results.

> P.S. I see you are using Cygwin 3.0.6, could it be a bug in Cygwin
> itself?  Is there a newer version of Cygwin?

No one mentions Emacs of git master in the Cygwin list so far.
I tried to update my Cygwin installation, but setup.exe said
it is up-to-date.  So, I'll try the snapshot later.

Thanks.