jsawk: use archive URL

Fixes #18798.
Tab#to_s returns a one-line summary of the receipt
info: make use of Tab#to_s

Closes #18788.
audit: don't complain about postgis using postgresql
mpd: fix a number of build issues

 - When yajl is installed, the build system manages to find it even
   under superenv, so explicitly disable this option unless requested
 - Future-proof finding faad2 in non-/usr/local installs
 - Fix libshout deps