both winsock.h and winsock2.h also offer INADDR_NONE, at least using MinGW's w32api headers.
Index: configure.ac
===================================================================
--- configure.ac (revision 999)
+++ configure.ac (working copy)
@@ -205,7 +205,8 @@
# Solaris lacks this
AC_CHECK_DEFINE([INADDR_NONE], [netinet/in.h], [],
- [AC_DEFINE([INADDR_NONE], [0xffffffff], [Define INADDR_NONE if not found in <netinet/in.h>])])
+ [AC_CHECK_DEFINE([INADDR_NONE], [winsock2.h], [],
+ [AC_DEFINE([INADDR_NONE], [0xffffffff], [Define INADDR_NONE if not found in <netinet/in.h>])])])
#### Check for libs ####
