if DB_LOCK not set, pin page across calls and don't copy key/data pair

4.4BSD snapshot (revision 8.1); add 1993 to copyright

break BTF flags up into btree/recno (B_, R_) categories

add BTF_EOF to test instead of bt_reof
clean up mmap and file pointer uses in recno interface

strings.h -> string.h

move db.h to the end of the includes, make compat.h work better

return RET_SPECIAL if R_PREV and at record 1; check for in memory
trees; use __rec_ret to return the keys

lint

make CURSOR of recno 0 do the right thing; copy the key out, too

redo cursor implementation, __rec_search interface

Rev #2. Redo the btree code add recno's and checkpoint