diff --git a/HySoP/setup.py.in b/HySoP/setup.py.in
index 2d04ab1e16d0a874689f4a4758b959e6eb66f37f..4ac918033ce5e1ab276fb6ad210f02dc958c583f 100644
--- a/HySoP/setup.py.in
+++ b/HySoP/setup.py.in
@@ -54,10 +54,11 @@ if(enable_fortran is "ON"):
     parmes_libdir = ['@CMAKE_BINARY_DIR@/src']
     parmeslib = ['@PARMES_LIBRARY_NAME@']
     f2py_options = ['--no-lower']
-
+    fortran_src = []
     withfftw = "@WITH_FFTW@"
     if(withfftw is "ON"):
-        fortran_src = [fortran_dir+'parameters.f90',fortran_dir+'fftw2py.f90']
+        fortran_src.append(fortran_dir+'parameters.f90')
+        fortran_src.append(fortran_dir+'fftw2py.f90')
         fftwdir = '@FFTWLIB@'
         fftwdir = os.path.split(fftwdir)[0]
         parmeslib.append('fftw3')