diff --git a/setup.py b/setup.py
index 6173ab2..136e0a1 100644
--- a/setup.py
+++ b/setup.py
@@ -1607,7 +1607,7 @@
             # finding some -z option for the Sun compiler.
             extra_link_args.append('-mimpure-text')
 
-        elif sys.platform.startswith('hpux'):
+        elif sys.platform.startswith('hp-ux'):
             extra_link_args.append('-fPIC')
 
         ext = Extension('_ctypes',