diff --git a/configure b/configure
index d47a098ef89..13303e36cc0 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 1.401 .
+# From configure.in Revision: 1.402 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.53 for python 2.3.
 #
@@ -1252,6 +1252,15 @@ cat >>confdefs.h <<\_ACEOF
 _ACEOF
 
 
+# The later defininition of _XOPEN_SOURCE and _POSIX_C_SOURCE disables
+# certain features on NetBSD, so we need _NETBSD_SOURCE to re-enable
+# them.
+
+cat >>confdefs.h <<\_ACEOF
+#define _NETBSD_SOURCE 1
+_ACEOF
+
+
 define_xopen_source=yes
 
 # Arguments passed to configure.
diff --git a/configure.in b/configure.in
index 765e8bf94a5..f4956171830 100644
--- a/configure.in
+++ b/configure.in
@@ -34,6 +34,11 @@ SOVERSION=1.0
 # on Linux, so we need _GNU_SOURCE to re-enable them (makedev, tm_zone).
 AC_DEFINE(_GNU_SOURCE, 1, [Define on Linux to activate all library features])
 
+# The later defininition of _XOPEN_SOURCE and _POSIX_C_SOURCE disables
+# certain features on NetBSD, so we need _NETBSD_SOURCE to re-enable
+# them.
+AC_DEFINE(_NETBSD_SOURCE, 1, [Define on NetBSD to activate all library features])
+
 define_xopen_source=yes
 
 # Arguments passed to configure.
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 93ef15146d3..705976d6d81 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -817,6 +817,9 @@
 /* Define to 1 if on MINIX. */
 #undef _MINIX
 
+/* Define on NetBSD to activate all library features */
+#undef _NETBSD_SOURCE
+
 /* Define _OSF_SOURCE to get the makedev macro. */
 #undef _OSF_SOURCE