Include myselect.h -- needed on some platforms.
diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 46bf8da..ea0c8b1 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -288,6 +288,7 @@
 #ifdef WITH_THREAD
 #ifndef MS_WINDOWS
 #include "mytime.h"
+#include "myselect.h"
 
 /* Millisecond sleep() for Unix platforms. */