diff --git a/configure b/configure
index 8b4e544..3f8459d 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 52455 .
+# From configure.in Revision: 52457 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.59 for python 2.5.
 #
@@ -1555,6 +1555,11 @@
   # Reconfirmed for OpenBSD 3.3 by Zachary Hamm, for 3.4 by Jason Ish.
   OpenBSD/2.* | OpenBSD/3.[0123456789] | OpenBSD/4.[0])
     define_xopen_source=no;;
+  # Defining _XOPEN_SOURCE on NetBSD version prior to the introduction of
+  # _NETBSD_SOURCE disables certain features (eg. setgroups). Reported by
+  # Marc Recht
+  NetBSD/1.5 | NetBSD/1.5.* | NetBSD/1.6 | NetBSD/1.6.* | NetBSD/1.6A-S)
+    define_xopen_source=no;;
   # On Solaris 2.6, sys/wait.h is inconsistent in the usage
   # of union __?sigval. Reported by Stuart Bishop.
   SunOS/5.6)