Show that certificates are added to memory stores at the head rather
than the tail.

server: Print a more informative message when file_set_error or sock_get_error can't map errno to a status code.

Add missing prototypes.
Add a commented-out #include directive as a reminder.

Add a skeleton intshcut.h header declaring InetIsOffline(), and use it.

Better match the PSDK types and fix the winapi_check warnings.