build: minor compilation fix.

demos/tutorial/Makefile.am

@@ -3,7 +3,7 @@ include $(top_srcdir)/build/autotools/common.am
 
 noinst_PROGRAMS = 01_triangle 02_cube 03_noise 04_texture 05_easymesh \
                   06_sprite 07_input 08_fbo 11_fractal \
-                  12_voronoi
+                  12_voronoi 13_shader_builder
 
 01_triangle_SOURCES = 01_triangle.cpp 01_triangle.lolfx
 01_triangle_CPPFLAGS = $(AM_CPPFLAGS)