--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,7 @@
+2006-08-18  Bruno Haible  <bruno@clisp.org>
+
+	* bison-i18n.m4: New file, from bison.
+
 2006-08-18  Bruno Haible  <bruno@clisp.org>
 
 	* ls-mntd-fs.m4 (gl_LIST_MOUNTED_FILE_SYSTEMS): Also check for

new file mode 100644
--- /dev/null
+++ b/m4/bison-i18n.m4
@@ -0,0 +1,59 @@
+# bison-i18n.m4 serial 1 (bison-2.1)
+dnl Copyright (C) 2005 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Support for internationalization of bison-generated parsers.
+
+dnl BISON_I18N
+dnl should be used in configure.ac, after AM_GNU_GETTEXT. If USE_NLS is yes, it
+dnl sets BISON_LOCALEDIR to indicate where to find the bison-runtime.mo files
+dnl and defines YYENABLE_NLS if there are bison-runtime.mo files at all.
+AC_DEFUN([BISON_I18N],
+[
+  if test -z "$USE_NLS"; then
+    echo "The BISON-I18N macro is used without being preceded by AM-GNU-GETTEXT." 1>&2
+    exit 1
+  fi
+  BISON_LOCALEDIR=
+  if test "$USE_NLS" = yes; then
+    dnl AC_PROG_YACC sets the YACC variable; other macros set the BISON variable.
+    if test -n "$YACC"; then
+      case "$YACC" in
+        *bison*)
+          if ($YACC --print-localedir) >/dev/null 2>&1; then
+            BISON_LOCALEDIR=`$YACC --print-localedir`
+          fi
+          ;;
+      esac
+    else
+      if test -n "$BISON"; then
+        if test "$BISON" != ":"; then
+          if ($BISON --print-localedir) >/dev/null 2>&1; then
+            BISON_LOCALEDIR=`$BISON --print-localedir`
+          fi
+        fi
+      fi
+    fi
+    AC_SUBST([BISON_LOCALEDIR])
+    if test -n "$BISON_LOCALEDIR"; then
+      USER_LINGUAS="${LINGUAS-%UNSET%}"
+      if test -n "$USER_LINGUAS"; then
+        BISON_USE_NLS=yes
+      else
+        BISON_USE_NLS=no
+      fi
+    else
+      BISON_USE_NLS=no
+    fi
+  else
+    BISON_USE_NLS=no
+  fi
+  if test $BISON_USE_NLS = yes; then
+    AC_DEFINE([YYENABLE_NLS], 1,
+      [Define to 1 to internationalize bison runtime messages.])
+  fi
+])