diff --git a/src/Main/Makefile.am b/src/Main/Makefile.am
index 1a1a3d798..9a3064fda 100644
--- a/src/Main/Makefile.am
+++ b/src/Main/Makefile.am
@@ -1,3 +1,6 @@
+EXTRA_DIST = 3dfx.sh runfgfs.in runfgfs.bat.in \
+             fg_os_sdl.cxx fg_os.cxx fg_os.hxx
+
 if ENABLE_MPLAYER_AS
 MPLAYER_LIBS = $(top_builddir)/src/MultiPlayer/libMultiPlayer.a
 else
@@ -24,8 +27,6 @@ endif
 
 AM_CXXFLAGS = -DPKGLIBDIR=\"$(pkgdatadir)\"
 
-EXTRA_DIST = 3dfx.sh runfgfs.in runfgfs.bat.in
-
 bin_PROGRAMS = fgfs metar
 
 noinst_SCRIPTS = runfgfs.bat runfgfs