Introduce and apply krb5_storage_from_socket

On Windows a file descriptor is an int value allocated by the
local module instance of the C Run Time Library.  A socket handle is a
SOCKET value allocated by a Winsock Provider for the requested family and
protocol.   These two values cannot be mixed and there is no mechanism for
converting between the two.   The _get_osfhandle() and _open_osfhandle()
functions can work with a standard HANDLE (file, pipe, etc) but cannot be
used for a SOCKET.

The Heimdal krb5_storage_from_fd() routine counted on the osf conversion
functions working on SOCKET values.  Since they do not any attempt to call
krb5_storage_from_fd() on a socket resulted in an assertion being thrown
by the C RTL.

Another problem is SOCKET value truncation when storing a 64-bit value
into a 32-bit int.

To address these problems a new krb5_storage_from_socket() routine is
introduced.  This routine setups a krb5_storage that stores a socket value
as a rk_socket_t and provides a set of helper routines that always use
network ready functions.

The krb5_storage_from_fd() routines no longer use net_read() and
net_write() but provide helpers that follow their logic so that pipes can
be processed.

All call sites that allocate a socket now store the socket as rk_socket_t
and call krb5_storage_from_socket().

All locations that previously called the bare close() on a socket value
now call rk_closesocket().

Change-Id: I045f775b2a5dbf5cf803751409490bc27fffe597

lib/krb5/NTMakefile

@@ -147,6 +147,7 @@ libkrb5_OBJS =			\
 	$(OBJ)\store_emem.obj		    \
 	$(OBJ)\store_fd.obj		    \
 	$(OBJ)\store_mem.obj		    \
+	$(OBJ)\store_sock.obj		    \
 	$(OBJ)\ticket.obj		    \
 	$(OBJ)\time.obj			    \
 	$(OBJ)\transited.obj		    \
@@ -297,6 +298,7 @@ dist_libkrb5_la_SOURCES =			\
 	store_emem.c				\
 	store_fd.c				\
 	store_mem.c				\
+	store_sock.c				\
 	pcache.c				\
 	plugin.c				\
 	ticket.c				\