bug#27527: 25.2; start-process crash on Windows with 64bit .NET executable

[Eli Zaretskii <eliz@gnu.org>]

> From: Saulius Menkevičius <saulius.menkevicius@gmail.com>
> Date: Thu, 29 Jun 2017 12:41:55 +0300
> 
> The issue was encountered when debugging a problem with omnisharp-emacs
> package where starting a server process (written for and running in a  .NET/CLR VM)
> crashes emacs with a segfault.
> 
> Recompiling with -g -O0 has revealed a problem in implementation of
> w32_executable_type in src/w32proc.c where the code is attempting to list
> DLL imports in a binary but the import table points to NULL. This code works for
> .NET binaries compiled for x86 so the problem is specific to 64 bit Windows / .NET DLLs.
> 
> The callstack of a crash is below and I have a patch attached that fixes the problem. 
> The patch applies cleanly to both master and emacs-25 branches.

Thanks.

Can you send the diffs generated with the -b switch?  I think all you
did was to condition the use of the import directory on its being
non-NULL, but it's hard to tell judging just by the diffs you posted.