Blender Git Loki

Fix broken multi-lib linking, and remove Main locking around core linking code for now.

We need to append to linklist, or our library indices would be reversed compared to lib list...

As for locking, we need reentrant one here if we want to use it. :(

Lock bmain around core part of linking code now, this is much safer imho!

This also means we need to ensure no code called from there tries to lock again bmain
(no reentrant spinlock, arg :/).

Add reload lib code, and various fixes (some to be backported to other working branches actually).

Merge branch 'lib-link-rework-temp' into id-remap

Merge branch 'missing-libs' into id-remap

Merge branch 'master' into id-remap

Merge branch 'master' into missing-libs

Merge branch 'master' into lib-link-rework-temp

Merge branch 'lib-link-rework-temp' into id-remap

Merge branch 'missing-libs' into id-remap

Merge branch 'master' into lib-link-rework-temp

Merge branch 'master' into missing-libs

Relocate: remove old lib datablocks after relocate, if no ID comes from it anymore.

Attempt to handle correctly LIB_EXTERN vs. LIB_INDIRECT ID flags.

This is far from simple, and most likely not yet fully working, but we have a base...

Some fixes, add basic wrapper code needed for reload feature (not yet implemented).

Merge branch 'lib-link-rework-temp' into id-remap

Also, fix some issues in previous code.

Some naming cleanup.

Rework a bit new liblink code, to use our beloved memarena instead of ugly pile of malloc.

Performances are not an issue at all here, but it makes code slightly simpler, avoids
a loop over ghash of libs, avoids some potential mem fragmentation, and will be easier
with lib relocate code too in future...

Consider proxy objects as 'linked' ones when it comes to ID remapping.

Reason is, on next fileread, proxy will be assigned with its target's data again...
Note that this may not be true about all its datablocks pointers - but proxy objects
are really brittle in current code anyway, they could use a serious work as well.

Moar cleanup, some fixes towards sanier handling of remap & indirect data...

Proxy are still not correctly handled here though.