Include patchlevel.h (to ensure it is distributed with the rest).
diff --git a/Python/pythonmain.c b/Python/pythonmain.c
index 85cb650..aee8664 100644
--- a/Python/pythonmain.c
+++ b/Python/pythonmain.c
@@ -24,6 +24,8 @@
 
 /* Python interpreter main program */
 
+#include "patchlevel.h"
+
 #include "allobjects.h"
 
 #include "grammar.h"