./configure \
	--disable-wtmp \
	--without-pie \
	CPPFLAGS='-I/src/oasis/out/pkg/zlib/include' \
	LDFLAGS='-L/src/oasis/out/pkg/libressl -L/src/oasis/out/pkg/openbsd -L/src/oasis/out/pkg/zlib' \
	LIBS='-lcrypto -lbsd'

Several changes were made:

SECCOMP_AUDIT_ARCH, SANDBOX_SECCOMP_FILTER, and SANDBOX_RLIMIT were removed and instead defined in gen.lua dependent on the target toolchain architecture.
HAVE_STRNVIS was undefined because although we do build it into libbsd.a, we don't include the whole openbsd header directory.
HAVE_PLEDGE is defined because we have a stub definition in pkg/openbsd/include/unistd.h.
SIZEOF_* are undefined because they are only used if C99 int*_t are not available.
_PATH_BTMP, _PATH_PASSWD_PROG, _PATH_SSH_PIDDIR are moved to a top section along with a number of other paths which are normally defined with flags by the Makefile or automatically by pathnames.h.