diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 6c230cc0a..c5634b867 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -88,6 +88,7 @@ set (FSRCS
   fchisq.f90
   fchisq65.f90
   fil3.f90
+  fil4.f90
   fil6521.f90
   filbig.f90
   fillcom.f90