GitLab

mdb_load wasn't properly inserting escaped backslashes into the data.
mdb_dump wasn't escaping backslashes when generating printable output.

and enforce exclusive access to environment. Also fix txn_begin/pick_meta
to use correct meta page, and reset the flag after successful commit.

Drop macro Y=MDB_FMT_Y, add Yu/Yd=MDB_PRIy(). Replace
Y"d..." -> Yd"...", Y"u..." -> Yu"..." / MDB_SCNy(u)"...".

Use 64 bit types consistently. This keeps database structures the
same size for MDB_VL32 and native 64 bit builds.

Try to exit cleanly to avoid leaving stale readers. Not
a critical issue since mdb_reader_check can take care of
them, but still cleaner.