Revert "eval.lisp: Fix lookup of symbols"
Revert "eval.lisp: Fix lookup of symbols"

My initial reasoning for this was due to forgetting that my interpreter had
decided to support auto-quoting, whereas this interpreter appears to treat an
undefined symbol as an error.

This reverts commit 5048a57a32308e590f4030cc094f5e9f32b47323.

danielwhite/microlisp