Issue #15835: Define PATH_MAX on HP-UX.
diff --git a/Python/fileutils.c b/Python/fileutils.c
index 501cb8c..976c04b 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -1,4 +1,5 @@
 #include "Python.h"
+#include "osdefs.h"
 #ifdef MS_WINDOWS
 #  include <windows.h>
 #endif