Index: src/libslic3r/PrintObject.cpp
--- src/libslic3r/PrintObject.cpp.orig
+++ src/libslic3r/PrintObject.cpp
@@ -25,6 +25,7 @@
 #include <oneapi/tbb/blocked_range.h>
 #include <oneapi/tbb/concurrent_vector.h>
 #include <oneapi/tbb/parallel_for.h>
+#include <oneapi/tbb/spin_mutex.h>
 #include <string_view>
 #include <utility>
 
