Dear Maintainer,

I have discovered that the utility chntpw fails to parse its
command line on an AArch64 machine, e.g. ,the following
invocation

# chntpw -l SAM

in the directory Windows/System32/config of a volume
that contains a Windows installation prints the usage
help instead of the user list.

This happens because command line parsing in chntpw
assumes that char is signed that is not true on the AArch64
platform. The attached patch fixes the issue.