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

[matthew green <mrg%eterna.com.au@localhost>]

OK, there are two problems with sparc.  one seems to be GCC 7
and one appears to be ... something in mid-late january i am
still tracking down.

/rescue binaries fail with GCC 7, which is why the qemu runs
are failing -- the installer crashes the same.

it is not static binaries, but something specific to the
crunchgen'd binaries i guess.

if i can't figure out the crunchgen problem i'll revert the
switch on sparc but others may want to skip SMP kernels on
sparc for now (and i *just* fixed it! argh.)


.mrg.