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.
Both coas() and skyw() want to iterate over a circular area with
radius vrange. They did that by iterating over a rectangle that
encloses the circle, skipping coordinates out of range. To "save
time", they used a rather odd predicate for "out of range", namely
"vrange * vrange < (j * j + 3 * k * k) / 4)".
The predicate is wrong. coastwatch and skywatch could see one sector
too far in certain directions for practical radar ranges, and up to
two sectors for not so practical tech 1900+ radar stations.
For instance, with j = 13 and k = 3, vrange = 7, the predicate
evaluates to false (49 < 48), i.e. in range. However, the true
distance is 8, i.e. out of range. Likewise, j = 22, k = 8, vrange =
13: 169 < 169, true distance 15.
Fix by iterating over the circle directly, without comparing
distances.
Use new pln_is_in_orbit() when we want to test for orbit specifically,
and test PLN_LAUNCHED when we want to test whether the plane not
sitting in the sector (because it is flying). This distinction is
pointless at this time, because the only way PLN_LAUNCHED gets set is
when a satellite goes into orbit. It will become useful in a later
commit, which will use PLN_LAUNCHED to mark flying planes.
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.
