TODO
* add block support for write ?
* validate WINAPI versions of fallback functions
* add fallback versions of
  - GetLastError
* add libcfile_codepage.h and codepage functions
* what about disk full on write errno = ENOSPC

Tests:
* move creation of temporary filename (mkstemp) into helper function
* add open close
* add write when opened with read ?
* add IO control tests ?
* add test to retrieve size from device ?

Notes:
* WINAPI ReadFile
  When the file is UNBUFFERED it appears that nNumberOfBytesToRead must be a
  multiple of sector size. Any other value will result in error 0x57
  (ERROR_INVALID_PARAMETER).

20120403
* Worked on stand-alone version
* see `git log' for more recent change log

