From 758fee15d9627556a3f0011973e83afb8d56d9be Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Sat, 31 Jul 2010 23:34:12 +0200
Subject: [PATCH] ansi-c++-opt: Provide option --enable-c++/--disable-c++ when
 possible.

---
 ChangeLog      |  6 ++++++
 m4/ansi-c++.m4 | 33 +++++++++++++++++++++------------
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 09bf87f6e..8532f0183 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 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.
 	* tests/test-readlink.h (test_readlink): Accept EINVAL as an
 	alternative to ENOTDIR.
diff --git a/m4/ansi-c++.m4 b/m4/ansi-c++.m4
index 0b024379f..b7bc53090 100644
--- 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 @@ dnl From Bruno Haible.
 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])
 ])
-- 
2.11.0