PATCH RFA: Build stages 2 and 3 with C++

[Ian Lance Taylor]

Ian Lance Taylor <iant@google.com> writes:

> I would like to propose this patch as a step toward building gcc using a
> C++ compiler.  This patch builds stage1 with the C compiler as usual,
> and defaults to building stages 2 and 3 with a C++ compiler built during
> stage 1.  This means that the gcc installed and used by most people will
> be built by a C++ compiler.  This will ensure that gcc is fully
> buildable with C++, while retaining the ability to bootstrap with only a
> C compiler, not a C++ compiler.  This will permit us to experiment with
> optionally using C++ for some code, using a #ifdef to select the C
> implementation or the C++ implementation.
>
> I would suggest that we consider releasing 4.7 this way, as a small
> trial for building gcc with C++.
>
> This is a big step, so I am sending the patch to both gcc@ and
> gcc-patches@ for comments.
>
> Bootstrapped and ran testsuite on x86_64-unknown-linux-gnu.
>
> Ian
>
>
> 2011-07-15  Ian Lance Taylor  <iant@google.com>
>
> 	* configure.ac: Add --enable-build-poststage1-with-cxx.  If set,
> 	make C++ a boot_language.  Set and substitute
> 	POSTSTAGE1_CONFIGURE_FLAGS.
> 	* Makefile.tpl (POSTSTAGE1_CONFIGURE_FLAGS): New variable.
> 	(STAGE[+id+]_CONFIGURE_FLAGS): Add $(POSTSTAGE1_CONFIGURE_FLAGS).
> 	* configure, Makefile.in: Rebuild.


I got agreement from two global reviewers and no objections.

I have committed this patch.

Please let me know about any problems.

Ian