Add ability to relocate constants using RelocSink

cranelift/simplejit/src/backend.rs

@@ -566,6 +566,18 @@ impl RelocSink for SimpleJITRelocSink {
             }
         }
     }
+
+    fn reloc_constant(&mut self, _offset: CodeOffset, reloc: Reloc, _constant: ir::ConstantOffset) {
+        match reloc {
+            Reloc::X86PCRelRodata4 => {
+                // Not necessary to record this unless we are going to split apart code and its
+                // jumptbl/rodata.
+            }
+            _ => {
+                panic!("Unhandled reloc");
+            }
+        }
+    }
 }
 
 struct SimpleJITStackmapSink {