Zap toylist.h, moving contents of global structures into DEFINE_GLOBALS()
macros in each C file, and making generated/globals.h from that.  Rename
"toy" to "this" along the way to avoid toy/toys confusion.
diff --git a/main.c b/main.c
index b7adeda..d9408f3 100644
--- a/main.c
+++ b/main.c
@@ -22,7 +22,7 @@
 // global context for this applet.
 
 struct toy_context toys;
-union toy_union toy;
+union global_union this;
 char toybuf[4096];
 
 struct toy_list *toy_find(char *name)