Missing mp3 write support after building, not sure how to debug why

[madsl]

Tried building audiotools both through gentoo's ebuild for 3.1.1 and locally from git, but there's something during the process that makes it so that audiotools-config reports that it does not support "Writable" for mp3 files. How can I debug what's doing that? I have both lame and libmpg123 installed.

Default verbosity level : debug

extraction arguments
  Format Readable Writable Default Quality
  ────── ──────── ──────── ───────────────
    aiff      yes      yes
    alac      yes       no
      au      yes      yes
    flac      yes       no               8
     m4a      yes      yes             100
     mp2      yes       no             192
     mp3      yes       no               2
     mpc      yes       no               5
     ogg      yes       no               3
    opus      yes       no              10
     spx       no       no
     tta      yes       no
     wav      yes      yes
      wv       no       no        standard

[sl1pkn07]

same here but also the rest encoders

extraction arguments
  Format Readable Writable Default Quality
  ────── ──────── ──────── ───────────────
    aiff      yes      yes
    alac      yes       no
      au      yes      yes
    flac      yes       no               8
     m4a      yes      yes             0.5
     mp2      yes       no             192
     mp3      yes       no               2
     mpc      yes       no               5
     ogg      yes       no               3
    opus      yes       no              10
     spx      yes      yes
     tta      yes       no
     wav      yes      yes
      wv      yes       no        standard