tdb: always set tdb->tracefd to -1 to be safe on goto fail
    
    metze
    (cherry picked from samba commit 85449b7bcc4bd7948bea38b5514a02357950a002)
Signed-off-by: Stefan Metzmacher <metze@samba.org>

    tdb: reset tdb->fd to -1 in tdb_close()
    
    So that erroneous double tdb_close() calls do not try to close() same
    fd again. This is like SAFE_FREE() but for fd.
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
    (cherry picked from samba commit b4424f8234a78a79fb2d71d46ca208b4f12e0f9e)
Signed-off-by: Stefan Metzmacher <metze@samba.org>

    tdb: detect tdb store of identical records and skip
    
    This can help with ldb where we rewrite the index records
    (cherry picked from samba commit d4c0e8fdf063f88032c32de7ece60d502b322089)
Signed-off-by: Stefan Metzmacher <metze@samba.org>

    tdb: rename 'struct list_struct' into 'struct tdb_record'
    
    metze
    (cherry picked from samba commit 3b62e250c066f44d0ab08a7db037b6b4f74a914b)
Signed-off-by: Stefan Metzmacher <metze@samba.org>

(Also, remove bogus test dependency for hdr include check)

Offer to run debugger when test fails, with breakpoint.

Add test for non-mmap tdbs.

add EXCLUDES= with more obscure modules.
use ccanlint for "make check", finally.

Unused since " tdb: no longer need seqnum store hack as we can read after prepare."