I built guile 2.0.11 with "configure --program-suffix=20".
guile was installed as .../bin/guile20
guild was installed as .../bin/guild20

The guild20 script references .../bin/guile when I was expecting .../bin/guile20 to be used:

#!/bin/sh
# -*- scheme -*-
prefix="/opt/local"
exec_prefix="${prefix}"
exec ${GUILE:-${exec_prefix}/bin/guile} $GUILE_FLAGS -e '(@@ (guild) main)' -s "$0" "$@"
!#