unprivileged install(1) with bmake

[coypu%sdf.org@localhost]

Hi folks,

I re-did a Makefile for a package with an outdated build system.
Now I'd like to put this in pkgsrc (now it's wip/slicot), and I get:

===> Installing for slicot-5.0+20101122
=> Generating pre-install file lists
=> Creating installation directories
#   install  /current/pkgsrc/wip/slicot/work/.destdir/usr/pkg/lib/libslicot.a
install  -c  -r -o root -g wheel -m 444  -a "ranlib -t" libslicot.a /current/pkgsrc/wip/slicot/work/.destdir/usr/pkg/lib/libslicot.a
install: /current/pkgsrc/wip/slicot/work/.destdir/usr/pkg/lib/libslicot.a.inst.lTLcbS: chown/chgrp: Operation not permitted
*** Error code 1


The makefile looks like this:

SRCS!= echo *.f

PREFIX?=		/usr/pkg
LIBDIR?=		${PREFIX}/lib
SHLIBINSTALLDIR?=	${PREFIX}/lib

LIB=		slicot
LDADD+=		-llapack -lblas
LDFLAGS+=	-L${LIBDIR} -Wl,-R,${LIBDIR}

.include <bsd.lib.mk>


What am I missing to make unprivileged installs work for pkgsrc?