greetings,

in https://gitlab.alpinelinux.org/alpine/tsc/-/issues/35 it was decided to raise
the x86 baseline to sse2, two releases ago.

it was however not done until now. of course, in practice the packaging was
hit or miss- some things implicitly opted-into sse2 anyway via build-system.
sometimes it was fixed, sometimes not (best effort).

this baseline change will now mean that going forward, every package is expected
to utilise sse2 on x86.

if you are using 3.17/3.18 then nothing should change.
  note 3.18: the kernel has PAE which might have issues like
  https://lists.alpinelinux.org/~alpine/users/%3C03307148-0c4f-2aff-a4c9-cf9900221db5%40dkcomm.net%3E

if you are using edge, and you have a CPU without sse2, then the hardware will
most likely not work with alpine linux anymore.

for posterity, the default is (gcc spec):
  --with=pentium-m --with-fpmath=sse

from the docs:
  @item pentium-m
  Intel Pentium M; low-power version of Intel Pentium III CPU
  with MMX, SSE, SSE2 and FXSR instruction set support.  Used by Centrino
  notebooks.

(the first thing on the --with-arch list with sse2).