I tried to implement StrToInt64ExA/W as a reply to bug #27633
I also corrected the comment in functions FormatInt() and FormatDouble() 
because, according to MSDN, GetNumberFormat() returns the number of characters 
written (or required) and not the number of bytes emitted:
http://msdn.microsoft.com/en-us/library/windows/desktop/dd318110%28v=vs.85%29.
aspx
I hope my first patch to WINE is correct and it could be useful.
Sincerely,

Carlo Bramini.

 BOOL WINAPI StrToIntExA(LPCSTR lpszStr, DWORD dwFlags, LPINT lpiRet)
 {
+  LARGE_INTEGER li;
+  BOOL bRes;
+
+  TRACE("(%s,%08X,%p)\n", debugstr_a(lpszStr), dwFlags, lpiRet);
+
+  // Test on lpszStr is done into StrToInt64ExA

+  if (!lpiRet)
+  {
+    WARN("Invalid lpiRet would crash under Win32!\n");
+    return FALSE;
+  }

+
+  bRes = StrToInt64ExA(lpszStr, dwFlags, &li.QuadPart);
+  if (bRes)
+    *lpiRet = li.u.LowPart;
+
+  return bRes;
+}