Static rb_default_rs 

pub unsafe static mut rb_default_rs: VALUE

This is the default value of ::rb_rs, i.e. "\n". It seems it has always been just a newline string since the beginning. Not sure why C codes has to use this, given there is no way for ruby programs to interface.

Also it has not been deprecated for unknown reasons.

Generated by rb-sys for Ruby mri-x86_64-linux-gnu-3.2.3