diff -Naur Python-2.6/Modules/_multiprocessing/multiprocessing.c Python-2.6-clean-patch/Modules/_multiprocessing/multiprocessing.c
--- Python-2.6/Modules/_multiprocessing/multiprocessing.c	2008-06-14 00:38:33.000000000 +0200
+++ Python-2.6-clean-patch/Modules/_multiprocessing/multiprocessing.c	2008-10-07 12:23:55.000000000 +0200
@@ -8,6 +8,13 @@
 
 #include "multiprocessing.h"
 
+#ifndef CMSG_SPACE
+#define CMSG_SPACE(len) (_CMSG_ALIGN(sizeof(struct cmsghdr)) + _CMSG_ALIGN(len))
+#endif
+#ifndef CMSG_LEN
+#define CMSG_LEN(len) (_CMSG_ALIGN(sizeof(struct cmsghdr)) + (len))
+#endif
+
 PyObject *create_win32_namespace(void);
 
 PyObject *pickle_dumps, *pickle_loads, *pickle_protocol;
diff -Naur Python-2.6/setup.py Python-2.6-clean-patch/setup.py
--- Python-2.6/setup.py	2008-09-30 02:15:45.000000000 +0200
+++ Python-2.6-clean-patch/setup.py	2008-10-07 12:23:34.000000000 +0200
@@ -1277,6 +1277,14 @@
                 )
             libraries = []
 
+        elif platform.startswith('aix'):
+            macros = dict(
+                HAVE_SEM_OPEN=1,
+                HAVE_SEM_TIMEDWAIT=0,
+                HAVE_FD_TRANSFER=1
+                )
+            libraries = ['rt']
+
         else:                                   # Linux and other unices
             macros = dict(
                 HAVE_SEM_OPEN=1,