during 'make install', pre-existing site-packages residents are recompiled. Twice.

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-08-28.14:53:14.003>
labels = ['extension-modules', 'build', 'expert-installation']
title = "during 'make install', pre-existing site-packages residents are recompiled. Twice."
updated_at = <Date 2016-08-28.15:09:22.717>
user = 'https://github.com/MattDMo'

bugs.python.org fields:

activity = <Date 2016-08-28.15:09:22.717>
actor = 'r.david.murray'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Build', 'Extension Modules', 'Installation']
creation = <Date 2016-08-28.14:53:14.003>
creator = 'MattDMo'
dependencies = []
files = []
hgrepos = []
issue_num = 27884
keywords = []
message_count = 2.0
messages = ['273824', '273825']
nosy_count = 2.0
nosy_names = ['r.david.murray', 'MattDMo']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue27884'
versions = ['Python 3.6']