build: make --shared-[...]-path work on Windows

The `-L<path>` syntax isn't recognized by link.exe, and gyp
doesn't translate it properly. Without this, link.exe generates
the following warning and fails to link:

```
LINK : warning LNK4044: unrecognized option '/LC:/Users/nornagon/...'; ignored
```

PR-URL: https://github.com/nodejs/node/pull/21530


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: João Reis <reis@janeasystems.com>