Example of debugging GCC with toplevel bootstrap

[Jason Merrill]

Paolo Bonzini wrote:
> 
>> So, how would I now get a cc1plus/f951/jc1/cc1 binary compiled by the 
>> stage0 (host) compiler?

> make stage1-bubble STAGE1_LANGUAGES=c,c++,fortran,java

Wow, that's awkward.

> I think that after I fix PR25670, as a side effect, you will also be 
> able to use the more intuitive target "all-stage1".  But I didn't think 
> of that PR much closely because it is about a target that was anyway 
> undocumented, and there are bigger fish to fry.

Remind me why it's a good idea to force me to mess with bootstrapping at 
all, when all I want is to build a copy of the compiler that I can use 
for debugging problems?  There has to be an easier way to do that.  My 
laptop builds stage1 reasonably fast, but a bootstrap takes several hours.

This is a serious regression for me.

Jason