diff -ruN constantph-main.orig/gromacs-constantph/src/gromacs/applied_forces/densityfitting/densityfitting.cpp constantph-main/gromacs-constantph/src/gromacs/applied_forces/densityfitting/densityfitting.cpp
--- constantph-main.orig/gromacs-constantph/src/gromacs/applied_forces/densityfitting/densityfitting.cpp	2023-03-21 14:25:14.929492000 +0100
+++ constantph-main/gromacs-constantph/src/gromacs/applied_forces/densityfitting/densityfitting.cpp	2023-03-21 14:25:56.962253000 +0100
@@ -53,6 +53,7 @@
 #include "gromacs/math/coordinatetransformation.h"
 #include "gromacs/math/multidimarray.h"
 #include "gromacs/mdtypes/imdmodule.h"
+#include "gromacs/selection/indexutil.h"
 #include "gromacs/utility/classhelpers.h"
 #include "gromacs/utility/exceptions.h"
 #include "gromacs/utility/keyvaluetreebuilder.h"