Core words

These words follow cross-compiled words, but unlike them, these
are self-bootstrapping and don't depend on the Cross Compiler.
They will typically be included in source form right after a
stage1 binary which will interpret it on boot and bootstrap
itself to a full intepreter, which can then be relinked with
the Relinker. There is no loader for these libraries because
you will typically XPACK (B267) them.

440 core                       447 readln                   
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