Add ImportC compiler to dmd

[Walter Bright]

On 5/12/2021 6:01 AM, Adam D. Ruppe wrote:
> On Sunday, 9 May 2021 at 20:57:06 UTC, Walter Bright wrote:
>> If you could add a C compiler to dmd with 3000 lines of code,
> 
> As of the time of this writing it has already grown to:
> 
> https://github.com/dlang/dmd/pull/12507
> 
> +3,905 −42
> 
> 30% overbudget just three days after the announcement. I stand by my prediction 
> that this is going to end up a LOT bigger than it looked at first.

LOL. Subtract out the changelog documentation, and all the comments.