[PATCH] Fix cache dir resolving on Windows

[Eli Zaretskii]

> From: orgads@gmail.com
> Cc: Orgad Shaneh <orgads@gmail.com>
> Date: Mon,  3 Jun 2019 22:37:16 +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..edb8a1fcda 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 ("USERPROFILE");
> +#endif
>    if (home != NULL)

This is against the MS platform recommendations regarding "known
folders", see

  https://docs.microsoft.com/en-us/windows/desktop/shell/knownfolderid
  https://docs.microsoft.com/en-us/windows/desktop/shell/csidl

But maybe we don't care about that.  I know that many applications
ported from Unix don't.