The support for duplicates is necessary for various use cases related
to config names, so let's upgrade to the latest version which brings
this support. This updates the cebtree code to commit 808ed67 (tag
0.5.0). A few tiny adaptations were needed:
- replace a few ceb_node** with ceb_root** since pointers are now
tagged ;
- replace cebu*.h with ceb*.h since both are now merged in the same
include file. This way we can drop the unused cebu*.h files from
cebtree that are provided only for compatibility.
- rename immediate storage functions to cebXX_imm_XXX() as per the API
change in 0.5 that makes immediate explicit rather than implicit.
This only affects vars and tools.c:copy_file_name().
The tests continue to work.
This is an import of the compact elastic binary trees at commit
a9cd84a ("OPTIM: descent: better prefetch less and for writes when
deleting")
These will be used to replace certain lists (and possibly certain
tree nodes as well). They're as fast (or even faster) than ebtrees
for lookups, as fast for insertion and slower for deletion, and a
node only uses 2 pointers (like a list).
The only changes were cebtree.h where common/tools.h was replaced
with ebtree.h which we already have and already provides the needed
functions and macros, and the addition of a wrapper cebtree-prv.h in
src/ to redirect to import/cebtree-prv.h.
