This patch is an addition to https://bugs.gentoo.org/attachment.cgi?id=914594

diff --git a/src/slic3r/GUI/FreeCADDialog.cpp b/src/slic3r/GUI/FreeCADDialog.cpp
index 822bc4e2d9..dfbb037ed0 100644
--- a/src/slic3r/GUI/FreeCADDialog.cpp
+++ b/src/slic3r/GUI/FreeCADDialog.cpp
@@ -64,7 +64,7 @@ namespace GUI {
     class ExecVar {
     public:
         boost::process::opstream pyin;
-        boost::asio::io_service ios;
+        boost::asio::io_context ios;
         std::future<std::string> data_out;
         std::future<std::string> data_err;
         std::unique_ptr<boost::process::child> process;