fix compilation with cygwin

closes: #307969

ChangeLog

@@ -1,3 +1,6 @@
+2008-01-09  Alessandro Zummo <a.zummo@towertech.it>
+	* sanei_tcp.c, fix compilation with cygwin.
+
 2008-01-02  m. allan noah <kitno455 a t gmail d o t com>
 	* AUTHORS, configure, configure.in, backend/Makefile.in,
 	  backend/dll.conf.in, backend/hs2p-saneopts.h,

sanei/sanei_tcp.c

@@ -48,6 +48,10 @@
 
 #include <sys/socket.h>
 
+#if defined(__CYGWIN__) && !defined(MSG_WAITALL)
+#define MSG_WAITALL  0x08
+#endif
+
 #define BACKEND_NAME sanei_tcp
 
 #include "../include/sane/sane.h"