fix: BSDi 2.1 requires a port seperate from BSDi 2.0{.1}

src/Makefile.global

src/backend/bootstrap/bootstrap.c

src/backend/optimizer/path/costsize.c

src/backend/port/bsdi_2_1/Makefile.inc

src/backend/port/bsdi_2_1/machine.h

src/backend/port/bsdi_2_1/port-protos.h

src/backend/port/bsdi_2_1/port.c

src/backend/postmaster/postmaster.c

src/backend/storage/ipc/s_lock.c

src/backend/utils/Gen_fmgrtab.sh

src/backend/utils/adt/misc.c

src/backend/utils/adt/numutils.c

src/backend/utils/error/elog.c

src/backend/utils/error/exc.c

src/mk/port/postgres.mk.bsdi_2_1