The "rec" command is now a symlink to the "play" command. Just have the ebuild make it and all will be fixed. This prevents all forms of easy command line sound recording! ln -s /usr/bin/play /usr/bin/rec is the temporary fix until the .ebuild maintainer does it him/herself.
Stealing bug.
Created a new revision (sox-12.17.3-r1) which takes care of that issue. -phoen][x-