valgrind shows "invalid file descriptor" when calling platform.system() on my machine.

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-11-24.16:32:00.856>
labels = ['type-bug', 'library']
title = 'valgrind shows "invalid file descriptor" when calling platform.system() on my machine.'
updated_at = <Date 2017-11-12.18:32:11.811>
user = 'https://github.com/MathieuDuponchelle'

bugs.python.org fields:

activity = <Date 2017-11-12.18:32:11.811>
actor = 'skrah'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2016-11-24.16:32:00.856>
creator = 'Mathieu_Du'
dependencies = []
files = []
hgrepos = []
issue_num = 28789
keywords = []
message_count = 3.0
messages = ['281640', '306126', '306129']
nosy_count = 3.0
nosy_names = ['gregory.p.smith', 'skrah', 'Mathieu_Du']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue28789'
versions = ['Python 3.4']