reuse string lits

runtime/src/scm.rs

@@ -193,7 +193,7 @@ impl std::hash::Hash for Symbol {
     }
 }
 
-pub fn make_symbol_off_heap (name : scm_bits) -> Symbol {
+fn make_symbol_off_heap (name : scm_bits) -> Symbol {
     Symbol ([ tc7_symbol, name ])
 }