Merge branch 'topic/v14.9.16-all.tests'
* topic/v14.9.16-all.tests:
mx-test.sh: add $MAILX_CC_ALL_TESTS_DUMPERR= hook
a_main_dump_doc(): add an UNUSED()
mx-test.sh: check(): also watch out for refs/remotes/origin/test-out
mx-test.sh: add --no-colour | $MAILX_CC_TEST_NO_COLOUR
Some: reenable amalgamation (#define a_X without #undefs)
mx-test.sh: cc_all_configs(): oops, pass through $MAXJOBS
mx-test.sh: t_headerpick: without OPT_REGEX, different cksum
mx-test.sh: fix some OPT_DOCSTRINGS / OPT_UISTRINGS misses
su_err_doc(): be EQ su_err_name() in su_STATE_REPRODUCIBLE