https://bugs.gentoo.org/946495
https://github.com/prusa3d/PrusaSlicer/issues/13799

Index: src/libslic3r/GCodeSender.cpp
--- src/libslic3r/GCodeSender.cpp.orig
+++ src/libslic3r/GCodeSender.cpp
@@ -113,7 +113,7 @@ GCodeSender::connect(std::string devname, unsigned int
     this->io.post(boost::bind(&GCodeSender::do_read, this));
     
     // start reading in the background thread
-    boost::thread t(boost::bind(&boost::asio::io_service::run, &this->io));
+    boost::thread t(boost::bind(&boost::asio::io_context::run, &this->io));
     this->background_thread.swap(t);
     
     // always send a M105 to check for connection because firmware might be silent on connect
