Add socket_ioctl_ptr_t

For Win32, this is actually the pointer type an ioctl() third
argument needs to be.  For other OSs, this is basically what an
FIONBIO third argument needs to be... there's really no restruction
at all on what arguments after the second to ioctl() need to be.

src/xpdev/sockwrap.h

@@ -30,6 +30,7 @@
 #if defined(_WIN32)	/* Use WinSock */
 typedef const char* socket_send_buffer_t;
 typedef char* socket_recv_buffer_t;
+typedef u_long* socket_ioctl_ptr_t;
 
 #ifndef _WINSOCKAPI_
 	#include <winsock2.h>	/* socket/bind/etc. */
@@ -54,6 +55,7 @@ typedef char* socket_recv_buffer_t;
 #elif defined __unix__		/* Unix-variant */
 typedef const void* socket_send_buffer_t;
 typedef void* socket_recv_buffer_t;
+typedef int socket_ioctl_ptr_t;
 
 #include <netdb.h>			/* gethostbyname */
 #include <sys/types.h>		/* For u_int32_t on FreeBSD */