non-bootstrap build always uses the system-compiler. Bug?

[U.Mutlu]

Brian Drummond wrote on 06/16/2018 03:51 PM:
> On Sat, 2018-06-16 at 14:38 +0200, U.Mutlu wrote:
>> Jonathan Wakely wrote on 06/16/2018 02:10 PM:
>>> On Sat, 16 Jun 2018 at 13:08, U.Mutlu <um@mutluit.com> wrote:
>>>
>>>>
>>> What you're seeing is exactly what is supposed to happen. If you
>>> want GCC
>>> to be built by the new compiler then don't use --disable-bootstrap.
>>
>> Yes, but the full-build takes a whoppy ~ 111 minutes here, whereas
>> the non-bootstrap build takes only 12 minutes to make. A big
>> difference.
>>
>> How can I use the quick build variant with the new compiler?
>> If I don't use --disable-bootstrap, as you suggest, then it takes,
>> as said, ~ 111 minutes to make... :-(
>>
> Can't you add CC=my_new_gcc and/or CPP=my_new_g++ to the make command
> for the second step?

Yeah, that seems to be the way to go.
Currently trying a variant of that method, indeed:

configure --help does not mention these variables:
   CC_FOR_BUILD
   GCC_FOR_BUILD
   CXX_FOR_BUILD
I'm currently trying via them.

If it fails, then I'll add also:
   CC
   CXX
and maybe also CPP and GCC (after consulting the Makefile)



> -- Brian