bug#39118: Segfault while building on 64-bit Cygwin

On Mon, Jan 20, 2020 at 11:38:35AM -0500, John Cowan wrote:
> Yes, gladly, but I don't know how to get one in this context.  Do I need to
> add some flags to the Makefile, and if so, where?  (It's a twisty maze of
> passages, all different.) . Note that this *is* a build with JIT enabled;
> when I disable it using the env variable, there are no errors and 3.0.0
> works fine.
> 
> Also, it may take some time, as I have to rebuild my Windows system.

I also tried building Guile 3.0.0 on Cygwin 3.1.x.  The failure comes from
trying to parse compiled .go files.

The last time that I had this sort of problem, it was because the
O_BINARY flag was dropped or missing when writing .go files, leading
to CR+LF characters in the compiled files.  And I diagnosed it by
byte-comparing Linux-compiled .go files with Cygwin-compiled .go
files, and by looking for CR+LF combinations in the compiled .go
files.

I don't know if that is what is happening here, but, I'll check that
next time I have a chance.

Thanks,
Michael