Index: include/ruby/win32.h
===================================================================
--- include/ruby/win32.h	(revision 27218)
+++ include/ruby/win32.h	(working copy)
@@ -401,7 +401,8 @@
 /* #undef va_end */
 
 /* winsock error map */
-#define EWOULDBLOCK	WSAEWOULDBLOCK
+/* EWOULDBLOCK is defined as 140 in errno.h 
+#define EWOULDBLOCK	WSAEWOULDBLOCK */
 #define EINPROGRESS	WSAEINPROGRESS
 #define EALREADY	WSAEALREADY
 #define ENOTSOCK	WSAENOTSOCK
Index: win32/win32.c
===================================================================
--- win32/win32.c	(revision 27218)
+++ win32/win32.c	(working copy)
@@ -170,6 +170,7 @@
     {	WSAEFAULT,			EFAULT		},
     {	WSAEINVAL,			EINVAL		},
     {	WSAEMFILE,			EMFILE		},
+    {	WSAEWOULDBLOCK,	EWOULDBLOCK	},
 };
 
 int