Revert os.py 1.75, and directly implement update.
Fixes #1110478 and #1100235.
diff --git a/Misc/NEWS b/Misc/NEWS
index 1d919aa..92d9422 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -45,6 +45,8 @@
 Library
 -------
 
+- Bug #1110478: Revert os.environ.update to do putenv again.
+
 - Bug #1103844: fix distutils.install.dump_dirs() with negated options.
 
 - os.{SEEK_SET, SEEK_CUR, SEEK_END} have been added for convenience.