Flatten the leaf nodes in the paged bounding volume tree
as good as possible. The implementation still assumes a
whole world database which actually holds for our usual
scenery.
This kind of work is done two times for different
flavours of bounding volume generation. Factor
out and use this in BVHPageNodeOSG.cxx and
BoundingVolumeBuildVisitor.hxx.
It's common to use SGTime to calculate the the Julian Date, without providing time-zone information. Don't warn in these cases, since the behaviour is fine.
Allow subsystem init to be incremental, i.e requiring repeated init calls until a 'done' code is returned. Use this to support incremental init in groups and the manager. (It would also be possible to support it in an individual subsystem).
Note that if you use the existing init() calls, behaviour is unchanged.
At least one Linux distribution packager of FG has complained that we're bundling expat in our binaries. To keep them happy, add the option (-DSYSTEM_EXPAT=1 at cmake time) to use the system expat instead.
For the moment (and simplicity), this requires building SIMGEAR_SHARED (which is fired to on by selecting the option).
Clang was complaining that SGSky has virtual methods, but no virtual destructor. It turns out we're never subclassing SGSky - it's used directly. Hence, remove all the 'virtual' attributes from its methods.
CMake has never supported the MIPS compatibility headers, or indeed building using MIPSpro. If someone wishes to re-add MIPS/IRIX support, I'm hoping they will be using a compiler with functional standard library headers!
Imitate Q_UNSUED from Qt, and provide a Simgear 'unused var' warning suppression macro. Fix up one place where the previous warning suppression attempt (assigning to self) was still producing a warning under clang.
Always create only two SimGear libraries: SimGearCore and SimGearStatic, regardless of whether we're building static or shared. This requires an updated to FindSimGear.cmake module, for the static configuration.
This eliminates the black borders on runways between threshold and
designation textures and also between two designation numbers.
Thanks to Emilian for tracking this down!
Distros like Debian/Ubuntu use architecture-specific directory structures
(like /usr/lib/x86_64-linux-gnu) which we cannot hardcode/guess, so we
really need to search the default paths.
