--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-03-05  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
+
+	Update AC_OPENMP macro for Lahey compiler on GNU/Linux.
+	* m4/openmp.m4 (AC_OPENMP): Sync from Autoconf.
+
 2011-03-03  Bruce Korb  <bkorb@gnu.org>
 
 	parse-duration: remove xalloc.h dependency

--- a/m4/openmp.m4
+++ b/m4/openmp.m4
@@ -1,4 +1,4 @@
-# openmp.m4 serial 8
+# openmp.m4 serial 9
 dnl Copyright (C) 2006-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -79,12 +79,14 @@
           dnl   IBM C (AIX, Linux)   -qsmp=omp
           dnl   Cray CCE             -homp
           dnl   NEC SX               -Popenmp
+          dnl   Lahey Fortran (Linux)  --openmp
           dnl If in this loop a compiler is passed an option that it doesn't
           dnl understand or that it misinterprets, the AC_LINK_IFELSE test
           dnl will fail (since we know that it failed without the option),
           dnl therefore the loop will continue searching for an option, and
           dnl no output file called 'penmp' or 'mp' is created.
-          for ac_option in -fopenmp -xopenmp -openmp -mp -omp -qsmp=omp -homp -Popenmp; do
+          for ac_option in -fopenmp -xopenmp -openmp -mp -omp -qsmp=omp -homp \
+                           -Popenmp --openmp; do
             ac_save_[]_AC_LANG_PREFIX[]FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
             _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $ac_option"
             AC_LINK_IFELSE([_AC_LANG_OPENMP],