diff --git a/src/gui/Makefile.am b/src/gui/Makefile.am
index 4ae4731d..83664b6d 100644
--- a/src/gui/Makefile.am
+++ b/src/gui/Makefile.am
@@ -2,5 +2,5 @@ AM_CPPFLAGS = -I$(top_srcdir)/include
 
 noinst_LIBRARIES = libgui.a
 libgui_a_SOURCES = sdlmain.cpp render.cpp render_normal.h render_scale2x.h \
-	midi.cpp midi_win32.h midi_oss.h
+	midi.cpp midi_win32.h midi_oss.h midi_coreaudio.h