Based on ideas from Jouk Jansen <joukj@hrem.nano.tudelft.nl>.
* src/tools/vms_shorten_symbol.c: New file, taken from
https://sourceforge.net/p/vms-ports/vmsshortsym/ci/default/tree/vms_shorten_symbol.c
with some minor edits to allow compilation with C++ and being included in
another source code file.
* src/tools/apinames.c: Include `vms_shorten_symbol.c`.
(PROGRAM_VERSION): Set to '0.5'.
(names_dump) [OUTPUT_VMS_OPT]: Call `vms_shorten_symbol` to get unique function
identifiers not longer than 31 characters.
Werner Lemberg