Re: bug relating to func_infer_tag

[Bruno Haible]

Hello Ralf,

> I think things would work if you used AC_PROG_CXX instead of
> hand-written similar functionality for setting CXX.  Automake and
> Libtool specifically discover this macro as a sign for use of C++

This is exactly the problem. It looks for AC_PROG_CXX and nothing else.
It does not give me the freedom to use an alternative for AC_PROG_CXX.

In my case, I don't want to use AC_PROG_CXX because it aborts the entire
configure script if it does not find a C++ compiler. Other people may
want to use a different macro is they prefer some vendor compiler instead
of g++.

> may tack code onto the end of it.

Automake and Libtool modify the code of AC_PROG_CXX. Can't you come up
with a better design than this?

> Using AC_PROG_CXX should enable you to drop use of internal
> _AM_DEPENDENCIES([CXX]).

No, this is not an option for me.

Look at this: Automake apparently defines
  CXXLINK = $(LIBTOOL) $(AM_LIBTOOLFLAGS) ...
by default, and
  CXXLINK = $(LIBTOOL) --tag=CXX $(AM_LIBTOOLFLAGS) ...
if it has spotted an LT_LANG([CXX]) invocation.

Why does is not define
  CXXLINK = $(LIBTOOL) --tag=CXX $(AM_LIBTOOLFLAGS) ...
unconditionally? When defining the variable CXXLINK, Automake knows that
its use it to link executables which contain C++ object files. That
requires the use of the C++ compiler, always. And the use of the C++
compiler as a libtool argument requires --tag=CXX. No?

Bruno