all VAX, PDP11: Add initial NAT based ethernet connectivity via SLiRP.

This should work on all byte addressable host systems using GCC/clang to build.

The QEMU slirp code has been pried out of QEMU and stubs have been created to solve where the current slirp is entangled with the QEMU code.  Ths slirp/simh directory contains all the necessary include and glue files to make this useful.  Everything in the slirp directory is unmodified QEMU code.

slirp/simh/qemu/qapi/string-input-visitor.h

@@ -0,0 +1,25 @@
+/*
+ * String parsing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef STRING_INPUT_VISITOR_H
+#define STRING_INPUT_VISITOR_H
+
+#include "qapi/visitor.h"
+
+typedef struct StringInputVisitor StringInputVisitor;
+
+StringInputVisitor *string_input_visitor_new(const char *str);
+void string_input_visitor_cleanup(StringInputVisitor *v);
+
+Visitor *string_input_get_visitor(StringInputVisitor *v);
+
+#endif