toolchain: add a program for compiling ipc interface definitions

ifc can be used to compile .if files into self-contained header-only C
libraries, which can be used to send/receive messages that conform
to the described interface.

toolchain/ifc/type.c

@@ -0,0 +1,17 @@
+#include "type.h"
+
+#include <stdio.h>
+
+void type_print(const struct type *ty)
+{
+	switch (ty->ty_id) {
+	case TYPE_INT:
+		printf("int");
+		break;
+	case TYPE_STRING:
+		printf("string");
+		break;
+	default:
+		break;
+	}
+}