Do not use linkname by default to simplify debugging

common/ktls/ktls_stub_nolinkname.go

@@ -0,0 +1,15 @@
+//go:build linux && go1.25 && !badlinkname
+
+package ktls
+
+import (
+	"context"
+
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/logger"
+	aTLS "github.com/sagernet/sing/common/tls"
+)
+
+func NewConn(ctx context.Context, logger logger.ContextLogger, conn aTLS.Conn, txOffload, rxOffload bool) (aTLS.Conn, error) {
+	return nil, E.New("kTLS requires build flags `badlinkname` and `-ldflags=-checklinkname=0`, please recompile your binary")
+}