# HG changeset patch
# User Bruno Haible <bruno@clisp.org>
# Date 1280612052 -7200
# Node ID 8af6b9d12697fd102af6a350926113f4e73b1b5f
# Parent  ac49cf58cb8bec0f2c0634236b02ec5fb6586832
ansi-c++-opt: Provide option --enable-c++/--disable-c++ when possible.

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-07-31  Bruno Haible  <bruno@clisp.org>
+
+	ansi-c++-opt: Provide option --enable-c++/--disable-c++ when possible.
+	* m4/ansi-c++.m4 (gl_CXX_CHOICE): In Autoconf 2.66 or newer, provide
+	option --enable/disable-c++ instead of --enable/disable-cxx.
+
 2010-07-31  Bruno Haible  <bruno@clisp.org>
 
 	readlink, areadlink: Relax test a bit.
diff --git a/m4/ansi-c++.m4 b/m4/ansi-c++.m4
--- a/m4/ansi-c++.m4
+++ b/m4/ansi-c++.m4
@@ -1,4 +1,4 @@
-# ansi-c++.m4 serial 5
+# ansi-c++.m4 serial 6
 dnl Copyright (C) 2002-2003, 2005, 2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -15,17 +15,26 @@
 AC_DEFUN([gl_CXX_CHOICE],
 [
   AC_MSG_CHECKING([whether to use C++])
-  dnl It would be so nice if plus signs were supported in AC_ARG_ENABLE.
-  dnl Feature request submitted on 2010-03-13.
-  m4_ifdef([gl_CXX_CHOICE_DEFAULT_NO],
-    [AC_ARG_ENABLE([cxx],
-       [  --enable-cxx            also build C++ sources],
-       [CXX_CHOICE="$enableval"],
-       [CXX_CHOICE=no])],
-    [AC_ARG_ENABLE([cxx],
-       [  --disable-cxx           do not build C++ sources],
-       [CXX_CHOICE="$enableval"],
-       [CXX_CHOICE=yes])])
+  dnl Plus signs are supported in AC_ARG_ENABLE starting with autoconf-2.66.
+  m4_version_prereq([2.66],
+    [m4_ifdef([gl_CXX_CHOICE_DEFAULT_NO],
+       [AC_ARG_ENABLE([c++],
+          [  --enable-c++            also build C++ sources],
+          [CXX_CHOICE="$enableval"],
+          [CXX_CHOICE=no])],
+       [AC_ARG_ENABLE([c++],
+          [  --disable-c++           do not build C++ sources],
+          [CXX_CHOICE="$enableval"],
+          [CXX_CHOICE=yes])])],
+    [m4_ifdef([gl_CXX_CHOICE_DEFAULT_NO],
+       [AC_ARG_ENABLE([cxx],
+          [  --enable-cxx            also build C++ sources],
+          [CXX_CHOICE="$enableval"],
+          [CXX_CHOICE=no])],
+       [AC_ARG_ENABLE([cxx],
+          [  --disable-cxx           do not build C++ sources],
+          [CXX_CHOICE="$enableval"],
+          [CXX_CHOICE=yes])])])
   AC_MSG_RESULT([$CXX_CHOICE])
   AC_SUBST([CXX_CHOICE])
 ])