Fixes:
------

- Fix regression in 3.5.3 which fails to open files for stat(2) if the
  file is opened exclusively by another process.
  Addresses: https://cygwin.com/pipermail/cygwin/2024-April/255811.html

- Fix regression introduced in 3.5.0 when reading surrogate pairs (i.e.,
  unicode chars >= 0x10000) from the DOS command line.  Addresses:
  https://cygwin.com/pipermail/cygwin/2024-April/255807.html