building trunk fails due to C++

[Steve Kargl]

On Wed, Nov 09, 2011 at 11:10:05PM +0100, Tobias Burnus wrote:
> Steve Kargl wrote:
> >With top of tree, I'm seeing
> >
> >% ../gcc4x/configure --prefix=$HOME/work --enable-languages=c,fortran \
> >--disable-libmudflap --disable-bootstrap
> >% gmake
> 
> I think the issue is that by default the trunk is build (stage 1) by the 
> system C compiler and the next stages (Stage 2 and 3) are build by the 
> just-build C++ compiler. Thus, the C++ compiler supports the latest C++ 
> features and also the latest options.
> 
> If one now uses --disable-bootstrap, the system C++ compiler is used to 
> compile the first and last stage - but if the system C++ compiler is 
> slightly older, it might not support the newest compiler flags.

Yes, I understand that this is the problem.

> 
> I am not sure how to best solve this issues for --disable-bootstrap.
> 

Well, to start, whomever is responsible for libitm should remove
the -std=gnu++0x option.  Or, like, libgfortran, libitm should 
use the just built in-tree g++ to compile itself.

> Besides bootstrapping, you could use --disable-libitm or it might also 
> work to specify --disable-build-poststage1-with-cxx which also saves you 
> from building the C++ compiler if you don't want it.

Doing a full bootstrap adds 3+ hours on my laptop.  Oh well, I 
guess this is the price of progress.

-- 
Steve