Calling `CreateFileW` without making sure that the patname is really
`wchar_t` is a bad idea and can lead to unpredictable overreads. For
Windows CE, we impelemnt the missing API.
Fixes#1098 and !76 again.
* builds/windows/ftsystem.c (FT_Stream_Open): Call `CreateFileA`.
[_WIN32_WCE] (CreateFileA, FileSizeEx): Implement missing interfaces.