Add rules for stdlib, rustls, and stdio

[lucic71]

I also had to add support in Mapper for rules of typedef'ed scalars.

For exmaple:

typedef int rustls_io_result;
int -> ::rustls_ffi::rustls_io_result

Would clash with the already-existing rule of int because ToString strips the typedef and returns int instead of rustls_io_result. GetNameOfScalarTypedef returns rustls_io_result and the mapping becomes:

typedef int rustls_io_result;
rustls_io_result -> ::rustls_ffi::rustls_io_result

Initially I wanted to modify ToString to not strip the typedef, but that's a bigger change than I expected because it affects typedefs as size_t, uint32_t, etc.