--- brltty-3.9/configure.ac.gnusource	2007-10-17 17:19:31.000000000 +0200
+++ brltty-3.9/configure.ac	2008-02-28 14:30:57.000000000 +0100
@@ -678,7 +678,7 @@
 case "${host_os}"
 in
    linux*|gnu*|kfreebsd*)
-      brltty_cv_prog_cc_sysflags="-D_POSIX_C_SOURCE=2 -D_BSD_SOURCE -D_XOPEN_SOURCE=500"
+      brltty_cv_prog_cc_sysflags="-D_POSIX_C_SOURCE=2 -D_BSD_SOURCE -D_XOPEN_SOURCE=500 -D_GNU_SOURCE"
       ;;
    solaris*)
       brltty_cv_prog_cc_sysflags="-D_XOPEN_SOURCE=500 -D__EXTENSIONS__"