Saving C's **argv and cwd allows Ruby programs to reliably restart themselves
In a debugger often one gets to a state where one just wants to restart everything exactly the way the program was previously invoked.
It would helpful if Ruby saved **argv and cwd.
The attached patch saves these in RubyVM::OS_ARGV and RubyVM::OS_STARTUP_DIR. With this,
if a Ruby program wants to restart itself, it can run: