[racket-dev] raco pkg install should default to linking for filesystem packages

Hi all,

When I have a directory foo/, containing a single-collect package, and I 
install it with "raco pkg install foo/", it seems to copy the contents 
of the directory, meaning local edits are not found by the system. 
Instead I have to "raco pkg install --link foo/".

I would prefer it if "--link" were the default.

Cheers,
   Tony