dmd.dtoh-windows.dd

dtoh generates signatures for `extern(Windows)` and `extern(System)` functions.

When using the -HC switch, in addition to `extern(C)` and `extern(C++)` functions, `extern(Windows)` and `extern(System)` functions are output in the .h file as well.

Example D module:
---
extern(Windows) int hello()
{
    return 0;
}

extern(System) int myFriend()
{
    return 0;
}
---

Output with `-HC` switch:
---
// (full header omitted)

#ifndef _WIN32
#define EXTERN_SYSTEM_AFTER __stdcall
#define EXTERN_SYSTEM_BEFORE
#else
#define EXTERN_SYSTEM_AFTER
#define EXTERN_SYSTEM_BEFORE extern "C"
#endif

int32_t __stdcall hello();

EXTERN_SYSTEM_BEFORE int32_t EXTERN_SYSTEM_AFTER myFriend(x);
---