diff --git a/ChangeLog b/ChangeLog
index 262763f85..22c211e35 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2004-09-04  Jakub Jelinek  <jakub@redhat.com>
+
+	* configure.ac: grantpt is only available with -D_XOPEN_SOURCE
+	or -D_GNU_SOURCE under Linux.
+
 2004-09-04  Pavel S. Shirshov  <pavelsh@mail.ru>
 
 	* HACKING: Add to section "Programming Tips" g_free tip.
diff --git a/configure.ac b/configure.ac
index 590b44f59..244b76e4d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -142,6 +142,9 @@ aux*)
     LIBS="$LIBS -lposix"
     AC_DEFINE(_POSIX_SOURCE)
     ;;
+linux*)
+    AC_DEFINE(_GNU_SOURCE, 1, [Define to request GNU feature set on Linux])
+    ;;
 esac