chore: Make Forgejo build with go1.24

- [Go 1.24](https://groups.google.com/g/golang-announce/c/vYMfuq_XO6w)
is currently out for rc1.
- Using it to test unit tests and integration testing it failed horribly
with strange panics and errors, it is caused by
ca63101df4
and Forgejo trying to access the wrong internal data structures that
have been changed in Go 1.24.
- Use the new data structure for Go 1.24 and above.

modules/log/groutinelabel.go

@@ -1,3 +1,5 @@
+//go:build !go1.24
+
 // Copyright 2022 The Gitea Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 

modules/log/groutinelabel_go1.24.go

@@ -0,0 +1,38 @@
+//go:build go1.24
+
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package log
+
+import "unsafe"
+
+//go:linkname runtime_getProfLabel runtime/pprof.runtime_getProfLabel
+func runtime_getProfLabel() unsafe.Pointer //nolint
+
+// Struct definitions copied from: https://github.com/golang/go/blob/ca63101df47a4467bc80faa654fc19d68e583952/src/runtime/pprof/label.go
+type label struct {
+	key   string
+	value string
+}
+
+type LabelSet struct {
+	list []label
+}
+
+type labelMap struct {
+	LabelSet
+}
+
+func getGoroutineLabels() map[string]string {
+	l := (*labelMap)(runtime_getProfLabel())
+	if l == nil {
+		return nil
+	}
+
+	m := make(map[string]string, len(l.list))
+	for _, label := range l.list {
+		m[label.key] = label.value
+	}
+	return m
+}