re: README: gcc 7 switch coming to a port near you!

Andreas Gustafsson writes:
> Some days ago, matthew green wrote:
> > hopefully the sparc testbed will fix itself now.
> 
> It did, but MIPS is suffering from what looks like the same issue

yeah - i commited the hack for it already, but i think i've just 
found all the real fixes -- upstream's version of joerg's patch
to gcc/varasm.c plus additional fixes.

with this, crtbegin.o has a read-only .eh_frame, and libstdc++
builds sanely.

i'll be running some local tests before reverting any crunchgen
changes, so hold off any ramdisk etc size bumps for now.

thanks.


.mrg.