[3.7] closes bpo-27805: Ignore ESPIPE in initializing seek of append-mode files. (GH-17112) by benjaminp · Pull Request #17137

[3.7] closes bpo-27805: Ignore ESPIPE in initializing seek of append-mode files. (GH-17112) by benjaminp · Pull Request #17137 · python/cpython

…mode files. (GH-17112)

This change, which follows the behavior of C stdio's fdopen and Python 2's file object, allows pipes to be opened in append mode..
(cherry picked from commit 74fa9f7)

Co-authored-by: Benjamin Peterson <benjamin@python.org>