option.c: mingw64 only

* ext/socket/option.c (inet_ntop): something weird only on mingw64.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36568 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/socket/option.c

@@ -452,7 +452,7 @@ inet_ntop(int af, const void *addr, char *numaddr, size_t numaddr_len)
 #endif
     return numaddr;
 }
-#elif defined _WIN32
+#elif defined __MINGW64__
 # define inet_ntop(f,a,n,l)      rb_w32_inet_ntop(f,a,n,l)
 #endif