progs/glsl: add special Makefile rule for samplers_array

progs/glsl/Makefile

@@ -32,6 +32,7 @@ DEMO_SOURCES = \
 	pointcoord.c \
 	points.c \
 	samplers.c \
+	samplers_array.c \
 	shadow_sampler.c \
 	skinning.c \
 	texaaline.c \
@@ -188,7 +189,8 @@ samplers.o: $(UTIL_HEADERS)
 samplers: samplers.o $(UTIL_OBJS)
 
 
-samplers_array.o: $(UTIL_HEADERS)
+samplers_array.o: samplers.c $(UTIL_HEADERS)
+	$(APP_CC) $(CFLAGS) -DSAMPLERS_ARRAY $< -c -o $@
 
 samplers_array: samplers_array.o $(UTIL_OBJS)