Add ImportC compiler to dmd

[Ola Fosheim Grøstad]

On Thursday, 13 May 2021 at 06:56:07 UTC, Araq wrote:
> Sequence points, volatile, shared memory model, undefined 
> behavior, obscure aliasing rules... C is small and well 
> understood indeed -- when you chose to ignore all these things 
> that happen to contradict your narrative.

The goal of D is that tranlating C-code to D should be easy so D 
should adopt the sequence points and shared memory model of C/C++ 
anyway. Undefined behaviour is not relevant, as that means the 
compiler can define it any way it wants to as such code is not 
valid (should not be provided by the programmer), volatile is not 
frequently used outside embedded/kernel programming (and isn't 
difficult to implement anyway).