make install: make compileall optional

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-06-06.13:03:12.868>
labels = ['type-feature', 'expert-installation', '3.9']
title = 'make install: make compileall optional'
updated_at = <Date 2019-06-07.17:38:50.905>
user = 'https://github.com/blueyed'

bugs.python.org fields:

activity = <Date 2019-06-07.17:38:50.905>
actor = 'ned.deily'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Installation']
creation = <Date 2019-06-06.13:03:12.868>
creator = 'blueyed'
dependencies = []
files = []
hgrepos = []
issue_num = 37175
keywords = []
message_count = 2.0
messages = ['344812', '344976']
nosy_count = 2.0
nosy_names = ['blueyed', 'ned.deily']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue37175'
versions = ['Python 3.9']