bpo-29877: compileall: import ProcessPoolExecutor only when needed (GH-4856)


Importing ProcessPoolExecutor may hang or cause an error when the import
accesses urandom on a low resource platform

https://bugs.python.org/issue29877
(cherry picked from commit 1d817e4c8259f49602eefe9729743f6d9d748e8d)

Co-authored-by: Dustin Spicuzza <dustin@virtualroadside.com>
3 files changed