diff --git a/src/core/include/mp-units/ext/prime.h b/src/core/include/mp-units/ext/prime.h
index bb48956b..641c8039 100644
--- a/src/core/include/mp-units/ext/prime.h
+++ b/src/core/include/mp-units/ext/prime.h
@@ -32,6 +32,7 @@
 import std;
 #else
 #include <array>
+#include <bits/types.h>
 #include <cstddef>
 #include <cstdint>
 #include <numeric>