Had to reinstall my Raspberry Pi, how do I set up LDC2's environment values permamently?

[solidstate1991]

Due to a screwup on my part, I had to reinstall my Pi's OS (was 
quicker than looking up the potential solution), and since I 
don't need multiple separate versions of D, I want to do away 
with the `activate`/`deactivate` scripts, especially as this 
method isn't liked by certain applications. I once solved this, 
but I forgot it since it's a very unintuitive process.