Header consistency in dredd's default and mutant-tracking modes

[JonathanFoo0523]

Dredd uses different sets of headers for default mode and mutant-tracking mode. Since Dredd's headers are inserted at the beginning of the source file, they can "hide" the original program's headers and alter the definition of certain macros as described here. As a result, the macro definitions may differ between default mode and mutant-tracking mode. Additionally, there might be cases where void __dredd_prelude_start(); is required in one mode but not in the other.

To ensure consistency, Dredd should emit the union of #include headers from both modes.

[afd]

For the issue under Windows - if the experimental C11 atomics flag won't work it would be reasonable to guard the troublesome include lines with

#ifndef _MSC_VER
#include ...
#endif

This would skip it under Windows. Since mutant tracking presumably doesn't work under Windows at present, this would not make things any worse.

[afd]

But actually, see #343 (comment)