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.
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.
Use `short' instead of `unsigned short'. With variables, plague stage
and time were stored unsigned and used signed, which worked. Removal
of variables dropped the conversion to signed, which broke
plague_people() (plague.c rev. 1.6): stage didn't progress correctly
due to catastrophic underflow of time.
defines, import these defines into plague.h, drop var.h and include
plague.h where appropriate.
Remove some 'register' keywords at the same time.
No functional changes.
of copies made by getvec(). This is safe, because the new code
changes the item array precisely when the old code writes back a
changed copy.
(starv_ships, starv_units): Replace getvec() by direct, read-only item
access.
(feed_ship, feed_land): Remove parameter vec, work with sp->shp_item[]
and lp->lnd_item[] instead.
(plague_people): Change argument type to match uncopied item arrays.
sp->sct_item, sp->sct_effic, sp->sct_mobil instead. This is safe,
because the only caller passed a copy of sp->sct_item created with
getvec(), and infect_people() doesn't change it. Caller changed.
(infect_people): Rewrite plague risk computation for clarity.
To save space, the ancients invented `variables': a collection of
key-value pairs, missing means zero value, space for `enough' keys.
This complicates the code, as assigning to a `variable' can fail for
lack of space. Over time, `enough' increased, and for quite some time
now `variables' have been *wasting* space. This changeset replaces
them, except in struct mchrstr, struct lchrstr and struct pchrstr,
where they are read-only, and will be replaced later. It is only a
first step; further cleanup is required. To simplify and minimize
this necessarily huge changeset, the new item[] arrays have an unused
slot 0, and the old variable types V_CIVIL, ... are still defined, but
must have the same values as the item types I_CIVIL, ...
effect. Replace calls by struct assignment where possible. Replace
clear buffer, copy string to buffer by strncpy(). Use assignment to
clear when that's clearer. Replace overlapping copy through bounce
buffer by memmove(). Replace rest by standard memset() and memcpy().
Also use sizeof() instead of literal array sizes for robustness, and
instead of symbolic array sizes for clarity.
