[SAoC] 'DPP with Linux kernel headers' Project Thread

[Cristian Becerescu]

Update for week 2 of Milestone 2

- PRs from the previous week were successfully merged

- Tested running dpp to translate linux/virtio.h

In this phase, I've begun testing dpp with every linux header 
used by Alex Militaru's driver, starting with linux/virtio.h.

There are multiple cases where a function is declared through a 
macro, where the function return type is specified using 
__typeof(X)__ (e.g. __typeof(X)__ functionName()). The D 
translation would be something like:

typeof(X) functionName();

In C, X could be a variable of a certain type, the type itself 
(e.g. int), or an alias of a type.
In D, it is not valid code if X is either a certain type, or an 
alias of a type.

E.g.:
alias u32 = uint;

typeof(u32) f1(); // err
typeof(int) f2(); // err

Another issue is related to translating nested (on multiple 
levels) anonymous unions and structs (specifically in 
linux/slab.h, line 596), but I still have to wrap my head around 
this (because the generated code is a bit complicated).

An inconvenience is that on my machine, running dpp with virtio.h 
takes about 15 minutes, which slows down the debugging process 
with this specific header.