Encoding: Fix potential encoding issues with libarchive on Windows.

Because the 8bit string encoding in libarchive can be different than
the 8bit string encoding in CMake, change to call the wide version
of libarchive functions.  They are different if CMake is configured
to use UTF-8 as the internal encoding.
Merge topic 'libarchive-encoding' into next

46265beb Encoding: Fix potential encoding issues with libarchive on Windows.