Works around issue3863: freebsd4/5/6 and os2emx are known to have OS bugs when
calling fork() from a child thread. This disables that unit test (with a note
printed to stderr) on those platforms.
A caveat about buggy platforms is added to the os.fork documentation.
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index c223e54..14784fa 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -1646,6 +1646,10 @@
Fork a child process. Return ``0`` in the child and the child's process id in the
parent. If an error occurs :exc:`OSError` is raised.
+
+ Note that some platforms including FreeBSD <= 6.3, Cygwin and OS/2 EMX have
+ known issues when using fork() from a thread.
+
Availability: Unix.