make package run as root

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
while working on an upgrade of the sympa package, I'm running into an
issue: make install is run under su as root (as expected, as there is
no full destdir support) but privileges are dropped before 'make package':
=> Checking for missing run-time search paths in sympa-6.2.48
WARNING: Skipping check for SSP in DESTDIR mode.
=> Checking for work-directory references in sympa-6.2.48
=> Dropping ``root'' privileges.
=> Creating binary package /usr/tmp/mail/sympa/work/.packages/sympa-6.2.48.tgz
pkg_create: cannot open data file sympa/bin/sympa_newaliases-wrapper: Permission denied
mv: rename /usr/tmp/mail/sympa/work/.packages/sympa-6.2.48.tmp.tgz to /usr/tmp/mail/sympa/work/.packages/sympa-6.2.48.tgz: No such file or directory
*** Error code 1

It fails because sympa/bin/sympa_newaliases-wrapper is mode 1550 (and we want
it this way).
What is the proper way to have 'make package' run under su too ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--