HPCC-9936 Add option --keywords to eclcc to create xml list of reserved words

Signed-off-by: jamienoss <james.noss@lexisnexis.com>
Changes from review

Signed-off-by: jamienoss <james.noss@lexisnexis.com>
Merge pull request #6178 from jamienoss/issue9936-reserved-words-from-eclcc

HPCC-9936 Add option --keywords to eclcc to create xml list of reserved ...

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>