Re: [PATCH] top-level for libvtv: use normal (not raw_cxx) target exports

[Paolo Bonzini <bonzini@gnu.org>]

On 09/06/2015 16:22, Michael Haubenwallner wrote:
> Hi build machinery maintainers,
> 
> since we always build the C++ compiler now, I fail to see the need to still
> use RAW_CXX_TARGET_EXPORTS for libvtv.
> 
> The situation to expose the problem is:
> * Use a multilib-enabled x86_64-linux box.
> * Use a 64-bit (multilib-disabled) bootstrap compiler (binary image).
> $ configure --enable-multilib --with-system-zlib
> $ make bootstrap
> 
> When it comes to build the 32-bit libvtv, it breaks because of using
> "CC=/build/prev-gcc/xgcc -m32" "CXX=g++ -m32", while it should use
> "CC=/build/prev-gcc/xgcc -m32" "CXX=/build/prev-gcc/xg++ -m32" instead.
> 
> However, I'm not sure about the general question behind:
> Should it work to bootstrap the multilib-compiler using a non-multilib one?
> 
> This also needs above configure flags to work around two more but minor issues,
> which I'm unsure about whether I can/should fix at all:
> * --enable-multilib: Without this, the "user friendly check" is breaking,
>     since https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=205975

Why is it breaking?

> * --with-system-zlib: Without this, --enable-multilib tries to build a
>     32-bit zlib with "CC=/build/32/./prev-gcc/xgcc"

Ouch, that's a separate bug...  Arguably --with-system-zlib should be
the default these days (and should have been for 10 years or so).

The patch is ok.

Paolo