ENH: Added cygcheck knowledge for --ldd option on Cygwin.  Added error message for --ldd option when no tool is available but the option was still requested.
ENH: Added cygcheck knowledge for --ldd option on Cygwin.  Added error message for --ldd option when no tool is available but the option was still requested.

chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys