Partial patch from SF #452266, by Jason Petrone.
This changes Pythread_start_thread() to return the thread ID, or -1
for an error. (It's technically an incompatible API change, but I
doubt anyone calls it.)
diff --git a/Doc/lib/libthread.tex b/Doc/lib/libthread.tex
index 652058d..a2e5b7e 100644
--- a/Doc/lib/libthread.tex
+++ b/Doc/lib/libthread.tex
@@ -32,11 +32,10 @@
\end{datadesc}
\begin{funcdesc}{start_new_thread}{function, args\optional{, kwargs}}
-Start a new thread. The thread executes the function \var{function}
-with the argument list \var{args} (which must be a tuple). The
-optional \var{kwargs} argument specifies a dictionary of keyword
-arguments. When the
-function returns, the thread silently exits. When the function
+Start a new thread and return its identifier. The thread executes the function
+\var{function} with the argument list \var{args} (which must be a tuple). The
+optional \var{kwargs} argument specifies a dictionary of keyword arguments.
+When the function returns, the thread silently exits. When the function
terminates with an unhandled exception, a stack trace is printed and
then the thread exits (but other threads continue to run).
\end{funcdesc}