Aside from not being a good allocator, it's implemented on top of an existing malloc so it doesn't actually work.
Removing the calls to existing malloc on an embedded system would be trivial. Just point it at a predefined RAM area instead. It uses malloc only so you can play with it on a full featured OS, not because they left something out.
+1 for this
See the other comments here. It's overly simplistic, so not particularly efficient.
More importantly, it's implemented in terms of malloc in the first place:
> In this repository, that memory is supplied by malloc
Maybe one could make a LD_PRELOAD shim to re-export malloc from this lib.