mpg123: updated to 1.25.8

1.25.8
------
- mpg123:
-- Also disable cursor/video games for empty TERM (not just unset and dumb).
- libmpg123:
-- Accept changing mode extension bits when looking for next header for
  detecting free-format streams (bug 257).
-- Fix compute_bpf() for free format streams (needed to estimate track
  length and working fuzzy seeking in absence of an Info tag).

(adam)