Issue #15833: don't raise an exception if importlib can't write byte-compiled
files.
This fixes a regression introduced by 3.3. Patch by Charles-François Natali.
diff --git a/Misc/NEWS b/Misc/NEWS
index a9be99d..d747af5 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -127,6 +127,10 @@
Build
-----
+- Issue #15833: Fix a regression in 3.3 that resulted in exceptions being
+ raised if importlib failed to write byte-compiled files. This affected
+ attempts to build Python out-of-tree from a read-only source directory.
+
- Issue #15923: Fix a mistake in ``asdl_c.py`` that resulted in a TypeError
after 2801bf875a24 (see #15801).