Merge branch 'next'

* next:
  chore, extend print.*.{be,}ute files to 16 byte boundaries
  test, rewrite mux.19 regression (uta muxer) in terms of print.e.{be,}ute to avoid ariva specific mishandling of 0.0 m30 objects
  minor, just negate .mant in ffff_m30_{,23_}get_s() instead of reassigning it
  minor, use PRCHUNK_EOL throughout uta muxer to check for line ending
  chore, add UDEBUG macro to uta.c
  minor, abstract over character that ends prchunk lines, PRCHUNK_EOL
  minor, allow uta lines to start with `0', `?' followed by \t, or just a tab right away
  minor, check for the symbol length, avoid potential buffer overflow
  fix, abort line reading in uta muxer once the symbol is buggered somehow
  test, bring regression for uta muxer on lines that don't correspond to the uta format at all
  fix, actually convert hex numbers not just decimals in hex2int() in uta muxer
  test, provide regression tests for uta muxing hiccup
  fix, test, use stdout var to trigger diff