Issue #10517: After fork(), reinitialize the TLS used by the PyGILState_*
APIs, to avoid a crash with the pthread implementation in RHEL 5.  Patch
by Charles-François Natali.
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index d34f132..00a83b4 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -991,6 +991,7 @@
 PyOS_AfterFork(void)
 {
 #ifdef WITH_THREAD
+    _PyGILState_Reinit();
     PyEval_ReInitThreads();
     main_thread = PyThread_get_thread_ident();
     main_pid = getpid();