I don't understand what is going on with zstds header include structure, the paths are wrong and seem to assume that various directories are globally available..

Example:
cover.h in dictBuilder has
#include "mem.h"
#include "pool.h"

Neither exists in the same folder as cover, so I have to fix these by changing to

#include "../common/mem.h"
#include "../common/pool.h"

Then fix it again when I update zstd, after a few years I just have to ask..why?