core: allow to create hard-fork

pkg/config/hardfork_string.go

@@ -0,0 +1,24 @@
+// Code generated by "stringer -type Hardfork -linecomment ./pkg/config/hardfork.go"; DO NOT EDIT.
+
+package config
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[HF2712FixSyscallFees-1]
+}
+
+const _Hardfork_name = "HF_2712_FixSyscallFees"
+
+var _Hardfork_index = [...]uint8{0, 22}
+
+func (i Hardfork) String() string {
+	i -= 1
+	if i >= Hardfork(len(_Hardfork_index)-1) {
+		return "Hardfork(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	}
+	return _Hardfork_name[_Hardfork_index[i]:_Hardfork_index[i+1]]
+}