Fix issue with make install

core/utils.go

@@ -0,0 +1,15 @@
+package core
+
+import (
+	"github.com/cespare/xxhash/v2"
+)
+
+// nolint: errcheck
+func mkkey(h *xxhash.Digest, k1 string, k2 string) uint64 {
+	h.WriteString(k1)
+	h.WriteString(k2)
+	v := h.Sum64()
+	h.Reset()
+
+	return v
+}