lang/rust is super slow to build

[Pat Maddox]

Using poudriere, lang/rust is at 2 hours and counting on my 10-core i9 
w/ 128 gigs of RAM.

Does that sound right? It seems extremely slow to me, but this is my 
first time building it.

How long does it take others to build? What options are you using, or 
any other suggestions for shortening the time?

Pat