What changes to D would you like to pay for?

[Joakim]

The D foundation is planning to add a way for us to pay for 
changes we'd like to see in D and its ecosystem, rather than 
having to code everything we need ourselves or find and hire a D 
dev to do it:

"[W]e’re going to add a page to the web site where we can define 
targets, allow donations through Open Collective or PayPal, and 
track donation progress. Each target will allow us to lay out 
exactly what the donations are being used for, so potential 
donors can see in advance where their money is going. We’ll be 
using the State of D Survey as a guide to begin with, but we’ll 
always be open to suggestions, and we’ll adapt to what works over 
what doesn’t as we go along."
https://dlang.org/blog/2018/07/13/funding-code-d/

I'm opening this thread to figure out what the community would 
like to pay for specifically, so we know what to focus on 
initially, whether as part of that funding initiative or 
elsewhere. I am not doing this in any official capacity, just a 
community member who would like to hear what people want.

Please answer these two questions if you're using or would like 
to use D, I have supplied my own answers as an example:

1. What D initiatives would you like to fund and how much money 
would you stake on each? (Nobody is going to hold you to your 
numbers, but please be realistic.)

$50 - Parallelize the compiler, particularly ldc, so that I can 
pass it -j5 and have it use five cores _and_ not have the bloat 
of separate compiler invocation for each module/package, ie 
taking up more memory or time.

$30 - Implement H.S. Teoh's suggestion of having an automated 
build system to periodically check which dub packages are 
building with official compiler releases:

https://forum.dlang.org/post/mailman.3611.1536126324.29801.digitalmars-d@puremagic.com

$25 - Enable GC for the DMD frontend, so that dmd/gdc/ldc use 
less memory

I would also stake smaller amounts on various smaller bugs, if 
there were a better interface than bountysource and people were 
actually using it, ie users knew about and were staking money and 
D core devs were fixing those bugs and claiming that money.

2. Would you be okay with the patches you fund not being 
open-sourced for a limited time, with the time limit or funding 
threshold for open source release specified ahead of time, to 
ensure that funding targets are hit?

Yes, as long as everything is open-sourced eventually, I'm good.