diff --git a/src/external/LF_GL/PLGKT_LF.cpp b/src/external/LF_GL/PLGKT_LF.cpp
index 01a089b5..0d5d8c94 100644
--- a/src/external/LF_GL/PLGKT_LF.cpp
+++ b/src/external/LF_GL/PLGKT_LF.cpp
@@ -30,6 +30,7 @@
 #include <iostream>
 #include <cmath>
 #include <algorithm>
+#include <numbers>
 
 #include "PLGKT_LF.h"
 #include "PGKT_LF.h"