Switch flag generation from shell to C.
This should actually generate FLAG_longopt 0 #defines for disabled bare
longopts (ala ls without --color). Put temporary executables under "generated"
(including instlist for install).
diff --git a/toys.h b/toys.h
index b7acc27..caf9612 100644
--- a/toys.h
+++ b/toys.h
@@ -64,6 +64,7 @@
#define OLDTOY(name, oldname, opts, flags)
#include "generated/newtoys.h"
#include "generated/oldtoys.h"
+#include "generated/flags.h"
#include "generated/globals.h"
// These live in main.c