Why upgrade? I'm not a lawyer, but here's my take on the differences
to version 2:
* Software patents: better protection against abuse of patents to
prevent users from exercising the rights under the GPL. I doubt
we'll get hit with a patent suit, but it's a good move just on
general principles.
* License compatibility: compatible with more free licenses, i.e. can
"steal" more free software for use in Empire. I don't expect to steal
much, but it's nice to have the option.
* Definition of "source code": modernization of some details for today's
networked world, to make it easier to distribute the software. Not
really relevant to us now, as we normally distribute full source code.
* Tivoization: this is about putting GPL-licensed software in hardware,
then make the hardware refuse to run modified software. "Neat" trick
to effectively deny its users their rights under the GPL. Abuse was
"pioneered" by TiVo (popular digital video recorders). GPLv3 forbids
it. Unlikely to become a problem for us.
* Internationalization: more careful wording, to harden the license
outside the US. The lawyers tell us it better be done that way.
* License violations: friendlier way to deal with license violations.
This has come out of past experience enforcing the GPL.
* Additional permissions: Probably not relevant to us.
Also include myself in the list of principal authors.
The old code didn't honor command abortion at the following prompts:
* arm third argument
* deliver fourth argument (also simplify)
* fire third argument
* fly and recon prompt for carrier to land on: pln_onewaymission()
treated abort like empty input, which made planes attempt landing in
the sector.
* lmine second argument
* order d fourth argument
* power c nat(s) argument
* range second argument
* sail second argument
* shutdown both arguments (first one was broken in commit 84cfd670,
v4.3.10, second one never worked).
* tend third argument
(shutdown_initiate): New.
(shut): Use it. Shutdown in zero minutes no longer cancels the
shutdown, it just works. Use negative argument to cancel. Logging is
less detailed.
(shutdown_sequence): Internal linkage.
(pr_wall): All callers prefix text it with the same header. Move it
into the function.
other. Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special). New header types.h to
help avoid inclusion cycles. Sort include directives. Remove some
superflous includes.
thread entrypoints:
(lwpSelect, shutdown_sequence): Parameters didn't match thread entry
point prototype.
(lwpEntryPoint): Arguments didn't match thread entry point prototype.
Change linkage of functions without prototype declaration to static
where possible.
Remove some superflous declarations, replace others by suitable
includes.
