** undesirable in file name comparison, so lstrcmpiW() is only invoked in cases
** that are technically impossible and contradicting all known laws of physics.
*/
int win32_filenames_equal_nocase(
  const wchar_t *fn1,
  const wchar_t *fn2
){
  /* ---- Data types used by dynamically loaded API functions. -------------- */
  typedef struct { /* UNICODE_STRING from <ntdef.h> */
    USHORT Length;
    USHORT MaximumLength;
    PWSTR Buffer;
  } MY_UNICODE_STRING;
  /* ---- Prototypes for dynamically loaded API functions. ------------------ */
  typedef int (WINAPI *FNCOMPARESTRINGORDINAL)(LPCWCH,int,LPCWCH,int,BOOL);
  typedef VOID (NTAPI *FNRTLINITUNICODESTRING)(MY_UNICODE_STRING*,PCWSTR);
  typedef BOOLEAN (NTAPI *FNRTLEQUALUNICODESTRING)
    (MY_UNICODE_STRING*,MY_UNICODE_STRING*,BOOLEAN);
  /* ------------------------------------------------------------------------ */
  static FNCOMPARESTRINGORDINAL fnCompareStringOrdinal;
  static FNRTLINITUNICODESTRING fnRtlInitUnicodeString;
  static FNRTLEQUALUNICODESTRING fnRtlEqualUnicodeString;
  static int loaded_CompareStringOrdinal;
  static int loaded_RtlUnicodeStringAPIs;
  if( !loaded_CompareStringOrdinal ){
    fnCompareStringOrdinal = (FNCOMPARESTRINGORDINAL)
      GetProcAddress(GetModuleHandleA("kernel32"),"CompareStringOrdinal");
    loaded_CompareStringOrdinal = 1;
  }
  if( fnCompareStringOrdinal ){
    return fnCompareStringOrdinal(fn1,-1,fn2,-1,1)-2==0;
  }
  if( !loaded_RtlUnicodeStringAPIs ){
    fnRtlInitUnicodeString = (FNRTLINITUNICODESTRING)
      GetProcAddress(GetModuleHandleA("ntdll"),"RtlInitUnicodeString");
    fnRtlEqualUnicodeString = (FNRTLEQUALUNICODESTRING)
      GetProcAddress(GetModuleHandleA("ntdll"),"RtlEqualUnicodeString");
    loaded_RtlUnicodeStringAPIs = 1;
  }
  if( fnRtlInitUnicodeString && fnRtlEqualUnicodeString ){




    MY_UNICODE_STRING u1, u2;
    fnRtlInitUnicodeString(&u1,fn1);
    fnRtlInitUnicodeString(&u2,fn2);
    return (BOOLEAN/*unsigned char*/)fnRtlEqualUnicodeString(&u1,&u2,1);
  }
  /* In what kind of strange parallel universe are we? */
  return lstrcmpiW(fn1,fn2)==0;
}

/* Helper macros to deal with directory separators. */
#define IS_DIRSEP(s,i) ( s[i]=='/' || s[i]=='\\' )

** Call the GetFileInformationByHandleEx() function on Windows Vista, and resort
** to the GetFileInformationByHandle() function on Windows XP. The result string
** is allocated by mprintf(), or NULL on failure.
*/
char *win32_file_id(
  const char *zFileName
){
  /* ---- Data types used by dynamically loaded API functions. -------------- */
  typedef struct { /* FILE_ID_INFO from <winbase.h> */
    ULONGLONG VolumeSerialNumber;
    BYTE FileId[16];
  } MY_FILE_ID_INFO;
  /* ---- Prototypes for dynamically loaded API functions. ------------------ */
  typedef int (WINAPI *FNGETFILEINFORMATIONBYHANDLEEX)
    (HANDLE,int/*enum*/,MY_FILE_ID_INFO*,DWORD);
  /* ------------------------------------------------------------------------ */
  static FNGETFILEINFORMATIONBYHANDLEEX fnGetFileInformationByHandleEx;
  static int loaded_fnGetFileInformationByHandleEx;
  wchar_t *wzFileName = fossil_utf8_to_path(zFileName,0);
  HANDLE hFile;
  char *zFileId = 0;
  hFile = CreateFileW(
            wzFileName,
            0,
            FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
            NULL,
            OPEN_EXISTING,
            FILE_FLAG_BACKUP_SEMANTICS,
            NULL);
  if( hFile!=INVALID_HANDLE_VALUE ){
    BY_HANDLE_FILE_INFORMATION fi;
    MY_FILE_ID_INFO fi2;



    if( !loaded_fnGetFileInformationByHandleEx ){
      fnGetFileInformationByHandleEx = (FNGETFILEINFORMATIONBYHANDLEEX)
        GetProcAddress(
          GetModuleHandleA("kernel32"),"GetFileInformationByHandleEx");
      loaded_fnGetFileInformationByHandleEx = 1;
    }
    if( fnGetFileInformationByHandleEx ){
      if( fnGetFileInformationByHandleEx(
            hFile,/*FileIdInfo*/0x12,&fi2,sizeof(fi2)) ){
        zFileId = mprintf(
                    "%016llx/"