diff --git a/setup_functions.py b/setup_functions.py
index <HASH>..<HASH> 100644
--- a/setup_functions.py
+++ b/setup_functions.py
@@ -10,6 +10,8 @@ def get_starlink_macros():
     define_macros = []
     compiler = ccompiler.new_compiler()
 
+    # Force using 8bit integers?
+    define_macros.append(('NDF_I8', 1))
     define_macros.append(('HAVE_AST', 1))
 
     #undef SIZEOF_INT
ndf: ensure 8 bit integers in ndf are used