Turn the output of ldd into something you can put in a snapcraft.yaml stage-packages section

lddtostage

#!/bin/bash
#
# lddtostage
#
# usage:
#   lddtostage somebinary
#
# This will run through each linked library and figure out which deb
# it came from and print the list for pasting into a snapcraft.yaml
# in a 'stage-packages' section.
# Not perfect, and may include things like libc6 and nvidia-* which
# you likely don't want in your snap, but it's a good head start.

TMPDIR=$(mktemp -d)
LDD=$TMPDIR/LDD
PACKAGES=$TMPDIR/PACKAGES

ldd $1 | awk -F ' ' '{print $3}' | sed '/^$/d' | sed '/^(/d' > $LDD

while read p; do
  echo -n .
  dpkg -S $p | awk -F ' ' '{ print $1 }' | sed 's/:$//' >> $PACKAGES
done < $LDD
echo " "
sort $PACKAGES | uniq
rm -rf $TMPDIR