GNU gettext uses the gl_PROG_ANSI_CXX and also uses
LT_LANG([C++])
On a machine with a broken C++ compiler and no working C++ preprocessor, then
despite of configure option --disable-c++, configure bails out like this:
checking whether we are using the GNU C++ compiler... no
checking whether : accepts -g... no
checking dependency style of :... none
checking how to run the C++ preprocessor... /lib/cpp
configure: error: in
`/home/haible/multibuild-1039/hpux11.31/gettext-0.18.1/gettext-tools':
configure: error: C++ preprocessor "/lib/cpp" fails sanity check
See `config.log' for more details
configure: error: ./configure failed for gettext-tools
The reason is that LT_LANG([C++]) contains an invocation of AC_PROG_CXXCPP,
like this:
if test -n "$CXX" && ( test "X$CXX" != "Xno" &&
( (test "X$CXX" = "Xg++" && `g++ -v >/dev/null 2>&1` ) ||
(test "X$CXX" != "Xg++"))) ; then
AC_PROG_CXXCPP
else
_lt_caught_CXX_error=yes
fi
This means, if CXX=":", libtool's macro assumes that a C++ compiler exists
and works. But if CXX="" or CXX="no" it skips the test for the preprocessor.
This changes fixes the situation, allowing configure to progress when
--disable-c++ is given:
2011-06-05 Bruno Haible <br...@clisp.org>
ansi-c++-opt: Interoperability with libtool.
* m4/ansi-c++.m4 (gl_PROG_ANSI_CXX): When a C++ compiler is not found,
set the variable to "no", not to ":".
* NEWS: Mention the change.
--- NEWS.orig Mon Jun 6 00:27:57 2011
+++ NEWS Mon Jun 6 00:27:46 2011
@@ -12,6 +12,9 @@
Date Modules Changes
+2011-06-05 ansi-c++-opt When a C++ compiler is not found, the variable CXX
+ is now set to "no", not to ":".
+
2011-05-11 group-member The include file is changed from "group-member.h"
to <unistd.h>.
--- m4/ansi-c++.m4.orig Mon Jun 6 00:27:57 2011
+++ m4/ansi-c++.m4 Sun Jun 5 15:23:12 2011
@@ -1,4 +1,4 @@
-# ansi-c++.m4 serial 7
+# ansi-c++.m4 serial 8
dnl Copyright (C) 2002-2003, 2005, 2010-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -41,7 +41,7 @@
# gl_PROG_ANSI_CXX([ANSICXX_VARIABLE], [ANSICXX_CONDITIONAL])
# Sets ANSICXX_VARIABLE to the name of a sufficiently ANSI C++ compliant
-# compiler, or to ":" if none is found.
+# compiler, or to "no" if none is found.
# Defines the Automake condition ANSICXX_CONDITIONAL to true if such a compiler
# was found, or to false if not.
@@ -51,7 +51,7 @@
m4_if([$1], [CXX], [],
[gl_save_CXX="$CXX"])
if test "$CXX_CHOICE" = no; then
- CXX=":"
+ CXX=no
fi
if test -z "$CXX"; then
if test -n "$CCC"; then
@@ -62,7 +62,7 @@
[:])
fi
fi
- if test "$CXX" != ":"; then
+ if test "$CXX" != no; then
dnl Use a modified version of AC_PROG_CXX_WORKS that does not exit
dnl upon failure.
AC_MSG_CHECKING([whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) works])
@@ -114,9 +114,9 @@
CXX="$gl_save_CXX"])
AC_SUBST([$1])
- AM_CONDITIONAL([$2], [test "$$1" != ":"])
+ AM_CONDITIONAL([$2], [test "$$1" != no])
- if test "$$1" != ":"; then
+ if test "$$1" != no; then
dnl This macro invocation resolves an automake error:
dnl /usr/local/share/automake-1.11/am/depend2.am: am__fastdepCXX does not
appear in AM_CONDITIONAL
dnl /usr/local/share/automake-1.11/am/depend2.am: The usual way to
define `am__fastdepCXX' is to add `AC_PROG_CXX'
--
In memoriam Eduard Lederer <http://de.wikipedia.org/wiki/Eduard_Lederer>
