Common/FileUtil: Fix incorrect (32-bit) stat struct being used on Windows, which was hidden by a define in CommonFuncs.h.

[AdmiralCurtiss]

tldr: https://godbolt.org/z/9YeK6fToa

This is a really silly name clash between the stat struct, the _stat64 struct, and a #define that tries to make the stat function work on Windows by mapping the _stat64 function to it.

Over in FileUtil.h we have a member of FileInfo that is defined as follows:

dolphin/Source/Core/Common/FileUtil.h

Line 123 in 2a34b84

struct stat m_stat;

And over in CommonFuncs.h we have this define:

dolphin/Source/Core/Common/CommonFuncs.h

Line 29 in 2a34b84

#define stat _stat64

Additionally, sys/stat.h on Windows defines the following structs:

struct _stat64
{
    _dev_t         st_dev;
    _ino_t         st_ino;
    unsigned short st_mode;
    short          st_nlink;
    short          st_uid;
    short          st_gid;
    _dev_t         st_rdev;
    __int64        st_size;
    __time64_t     st_atime;
    __time64_t     st_mtime;
    __time64_t     st_ctime;
};

#define __stat64 _stat64 // For legacy compatibility

#if defined(_CRT_INTERNAL_NONSTDC_NAMES) && _CRT_INTERNAL_NONSTDC_NAMES && !defined _CRT_NO_TIME_T
    struct stat
    {
        _dev_t         st_dev;
        _ino_t         st_ino;
        unsigned short st_mode;
        short          st_nlink;
        short          st_uid;
        short          st_gid;
        _dev_t         st_rdev;
        _off_t         st_size;
        time_t         st_atime;
        time_t         st_mtime;
        time_t         st_ctime;
    };
#endif

This is a problem. If you include FileUtil.h without including CommonFuncs.h, you get the second struct but if you include CommonFuncs.h you instead get the first struct. FileUtil.cpp does the latter, so it gets the _stat64 struct. This means that different compilation units may have a different idea about the length of File::FileInfo, leading to potential stack corruption.

Note that I'm using __stat64 here instead of _stat64 because that's how the _wstat64 function (which we use) is defined in the MSVC docs: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/stat-functions?view=msvc-160

...I love code that works by accident.

[lioncash]

Oof this one's a doozy. Nice catch!