Building C++ with --enable-languages=c,fortran

[Ian Lance Taylor]

Thomas Koenig <tkoenig@netcologne.de> writes:

> I just noticed that C++ now appears to be built by default, even when
> only the C and fortran are specified.  The configure line
>
>
> ../trunk/configure  --prefix=$HOME --enable-languages=c,fortran
> --with-mpc=/usr/local --with-mpfr=/usr/local
>
> leads to the message
>
> checking for version 0.11 (revision 0 or later) of PPL... no 
>
> The following languages will be built: c,c++,fortran,lto
>
> I see recent changes by Ian in this area, but nothing in the ChangeLog
> suggests to me that this was intentional.

It is intentional.  In current mainline stages 2 and 3 are now by
default built with the C++ compiler, not the C compiler.  Therefore, the
C++ compiler must be built in stages 1 and 2, in order to use to build
the stages 2 and 3 compiler.  And then of course we build the C++
compiler in stage 3 in order to compare it.

The ChangeLog entry says that if --enable-build-poststage1-with-cxx is
set, C++ becomes a boot language.  That is what you are seeing.  I guess
what the ChangeLog entry does not say is that
--enable-build-poststage1-with-cxx is set by default.

Ian