bpo-32659: Solaris "stat" should support "st_fstype"

[jcea]

Trivial patch. The only questionable thing is the __sun define use. This is needed because autoconf doesn't test st_fstype. This would be something to patch in autoconf.

Example:

$ LD_LIBRARY_PATH=/home/cpython/cpython-bpo-32659 ./python
Python 3.7.0a4+ (default, Jan 25 2018, 03:34:04) 
[GCC 4.9.4] on sunos5
Type "help", "copyright", "credits" or "license" for more information.
>>> os.stat('/etc/passwd').st_fstype
'zfs'

https://bugs.python.org/issue32659

[jcea]

For reference, I checked Solaris 10, released in 2005, and this field is already present there:

NAME
     stat, lstat, fstat, fstatat - get file status
[...]
char     st_fstype[_ST_FSTYPSZ];
                                 /* Null-terminated type of filesystem */
[...]
SunOS 5.10          Last change: 13 Feb 2007                    1

[csabella]

Should there be a versionadded?

[jcea]

Good catch, @csabella . PR updated.

Thanks.

[bedevere-bot]

@jcea: Please replace # with GH- in the commit message next time. Thanks!