Speeding up importing Phobos files

[Boris-Barboris]

On Saturday, 19 January 2019 at 08:45:27 UTC, Walter Bright wrote:
> Andrei and I were talking on the phone today, trading ideas 
> about speeding up importation of Phobos files. Any particular D 
> file tends to import much of Phobos, and much of Phobos imports 
> the rest of it. We've both noticed that file size doesn't seem 
> to matter much for importation speed, but file lookups remain 
> slow.
>
> So looking up fewer files would make it faster.

Sounds rather strange that on modern operating systems, that 
cache files themselves and the metadata even more surely (VFS 
directory cache as an example), file lookup is a problem.

Calls to something like glob(3) could render the whole phobos 
directory tree to your memory in milliseconds.