Fix cache dir resolving on Windows

  From: Orgad Shaneh <orgads@gmail.com>

... when not running from MSYS environment, and HOME is not set.
---
 gdb/common/pathstuff.c | 4 ++++
 1 file changed, 4 insertions(+)
  

> From: orgads@gmail.com
> Cc: Orgad Shaneh <orgads@gmail.com>
> Date: Fri,  7 Jun 2019 09:27:19 +0300
> 
> From: Orgad Shaneh <orgads@gmail.com>
> 
> ... when not running from MSYS environment, and HOME is not set.
> ---
>  gdb/common/pathstuff.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/gdb/common/pathstuff.c b/gdb/common/pathstuff.c
> index 2b1669a5b9..59410fb61f 100644
> --- a/gdb/common/pathstuff.c
> +++ b/gdb/common/pathstuff.c
> @@ -231,6 +231,10 @@ get_standard_cache_dir ()
>  #endif
>  
>    const char *home = getenv ("HOME");
> +#ifdef _WIN32
> +  if (home == nullptr)
> +      home = getenv ("APPDATA");
> +#endif
>    if (home != NULL)
>      {
>        /* Make sure the path is absolute and tilde-expanded.  */

Thanks, this LGTM.
  

> Date: Fri, 07 Jun 2019 10:36:39 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> CC: gdb-patches@sourceware.org
> 
> >    const char *home = getenv ("HOME");
> > +#ifdef _WIN32
> > +  if (home == nullptr)
> > +      home = getenv ("APPDATA");
> > +#endif
> >    if (home != NULL)
> >      {
> >        /* Make sure the path is absolute and tilde-expanded.  */
> 
> Thanks, this LGTM.

Actually, I see that we mention HOME on Windows in the manual, in a
footnote that's part of the "Startup" node.  I think we should
document this addition there.  Would you like to add a change to the
manual as well?

Thanks.

P.S. I see that you don't have a copyright assignment on file, which
means we are limited in the amount of changes we can accept from you.
Would you like to start the legal paperwork of assigning to the FSF
the copyright for your changes?  If so, I will send you the form to
fill.
  

> From: Orgad Shaneh <orgads@gmail.com>
> Date: Fri, 7 Jun 2019 11:58:45 +0300
> 
> On Fri, Jun 7, 2019 at 11:01 AM Eli Zaretskii <eliz@gnu.org> wrote:
> > Actually, I see that we mention HOME on Windows in the manual, in a
> > footnote that's part of the "Startup" node.  I think we should
> > document this addition there.  Would you like to add a change to the
> > manual as well?
> 
> This refers to gdbinit, which probably should also be added a fallback
> to APPDATA. Anyway, it is not related to this patch, which is about
> the cache directory.

Oh, so we probe $HOME in more than one place?  Yes, I think we should
do this in all of those places, preferably through a single function.

> > P.S. I see that you don't have a copyright assignment on file, which
> > means we are limited in the amount of changes we can accept from you.
> > Would you like to start the legal paperwork of assigning to the FSF
> > the copyright for your changes?  If so, I will send you the form to
> > fill.
> 
> Sure.

Thanks, form sent off-list.
  

>> +#ifdef _WIN32
>> +  if (home == nullptr)
>> +      home = getenv ("APPDATA");

I think the assignment line is indented a bit too far -- should be 2
spaces over from the "if", per the GNU style.

thanks,
Tom