Revert "libltdl wants AM_MAINTAINER_MODE"

This reverts commit 4c6493e74798ee4836efecc234dded703763adf9.
Revert "move libltdl to 3rdparty/"

This reverts commit 6a9c636fb9573d3eb4232e2f970d077ff373d11b.
Remove unused variable
poll jobs on file upload too (bb #488)
fix error message priority (bb #488)

If one of the nodes replies 429, and the next one cannot be contacted/reports
other error, then previously we would show the 429 error.
Lower the priority of the 429 error, so we see the real error
(node down in this case).
keep retrying, even if job wait fails on initial upload

job wait can fail due to timeouts / node down, etc.
avoid some 'curlev_poll but nothing to poll' messages (bb #488)
when all retries fail on an upload mark it as failed
openbsd doesn't have ns_s_*
--replica=n
file extends cannot be retried on other nodes (bb #429)
sxls: print r:N for replica count N in -l mode
fix error for non-existing aliases (bb#460)
update current host after a retry (bb #493)
Bump version number
drop duplicate header
fix leak in sxcp
update docs, add NEWS
quickstart: add zlib to requirements
Must call sqlite3_initialize before calling sqlite3_test_control

If sqlite3 is built with THREAD_SAFE=1 it must be called to prevent a null
deref.