Several additional posix errnos are now used within Heimdal.
Add definitions for them.
With the introduction of VS2010 VC errno.h now includes definitions
for the full posix error number list. Instead of mapping errno values
to Winsock errors, use the new VS2010 assignments.
Change-Id: Ieb7c5efbcbedb1c10d56e5c8a63ddd58a15df9b1
269cf69f42