preinst is in libc6-dev-x32 2.19-18+deb8u10.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | #!/bin/sh
set -e
case $1 in
(upgrade|install)
# We want /usr/include/sys to be a normal directory instead
# of a symlink
if test -h /usr/include/sys ; then
rm -f /usr/include/sys
fi
;;
(*)
;;
esac
|