Trace greedy replaces $prefix and $exec_prefix

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-02-13.08:53:15.603>
labels = ['library', '3.9']
title = 'Trace greedy replaces $prefix and $exec_prefix'
updated_at = <Date 2020-02-17.13:51:48.856>
user = 'https://github.com/mathstuf'

bugs.python.org fields:

activity = <Date 2020-02-17.13:51:48.856>
actor = 'vstinner'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-02-13.08:53:15.603>
creator = 'mathstuf'
dependencies = []
files = []
hgrepos = []
issue_num = 39624
keywords = []
message_count = 8.0
messages = ['361949', '361955', '361958', '361970', '362031', '362131', '362137', '362146']
nosy_count = 2.0
nosy_names = ['vstinner', 'mathstuf']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue39624'
versions = ['Python 3.9']