Rework OS abstractions

- As much as possible avoid dragging system headers into translation
  units. This should avoid namespace pollution and, hopefully, speed up
  builds a little bit.

- Avoid leaning on the UCRT so much on Windows - prefer native win32
  calls and native file handles except where doing so is inconvenient
  (in particular, for stat(), which we might try and replace later).

- Also, switch from SystemFunction036 to ProcessPrng on Windows. This
  requires us to generate a stub for bcryptprimitives.dll because
  Microsoft haven't bothered to provide a link library, but the function
  is better-documented and seems to be a more direct under-the-hood call
  as well. Apparently it's what's used by the major web browsers these
  days, which seems like a good indication it's stable and trusted.

- Lastly, remove a bunch of functions and macros and stuff that weren't
  actually being used. It seems good to try and keep the scope of
  OS-dependent stuff relatively contained and only add to it when
  actually required.

1 files changed, 7 insertions, 4 deletions

diff --git a/src/ac.c b/src/ac.c
index 8b163b9..8c98cfb 100644
--- a/src/ac.c
+++ b/src/ac.c
@@ -17,6 +17,13 @@
 
 #include <stdlib.h>
 
+#ifdef _WIN32
+#include <Windows.h>
+#include <werapi.h>
+#else
+#include <sys/mman.h>
+#endif
+
 #include "alias.h"
 #include "bind.h"
 #include "chunklets/fastspin.h"
@@ -41,10 +48,6 @@
 #include "x86.h"
 #include "x86util.h"
 
-#ifdef _WIN32
-#include <werapi.h> // must be after Windows.h (via os.h)
-#endif
-
 FEATURE()
 REQUIRE(bind)
 REQUIRE(democustom)