diff --git a/src/gui/Makefile.am b/src/gui/Makefile.am
index 00fc5765..ec0a145a 100644
--- a/src/gui/Makefile.am
+++ b/src/gui/Makefile.am
@@ -1,5 +1,5 @@
 AM_CPPFLAGS = -I$(top_srcdir)/include
 
 noinst_LIBRARIES = libgui.a
-libgui_a_SOURCES = sdlmain.cpp render.cpp
+libgui_a_SOURCES = sdlmain.cpp render.cpp render_support.h