Fix build and run unit tests

Makefile

@@ -28,7 +28,7 @@ INCLUDE_DIRS =\
   $(SRC_DIRS)\
   $(CPPUTEST_HOME)/include
 
-PRDUCT_MAIN_OBJ = src/main.o
+PRODUCT_MAIN_OBJ = src/main.o
 
 include $(CPPUTEST_HOME)/build/MakefileWorker.mk
 
@@ -40,8 +40,8 @@ $(EVALUATOR_LIB) :
 .PHONY: product
 product : $(PRODUCT)
 
-$(PRODUCT): $(TARGET_LIB) $(PRDUCT_MAIN_OBJ) $(EVALUATOR_LIB) $(CPPUTEST_LIB)
+$(PRODUCT): $(TARGET_LIB) $(PRODUCT_MAIN_OBJ) $(EVALUATOR_LIB) $(CPPUTEST_LIB)
 	@echo 'Building target: $@'
-	$(CC) -o $@ -g $^ $(LD_LIBRARIES)
-	@echo 'Running the game. Go to your browser to play at http://localhst:8888'
-	./$(PRODUCT)
+	g++ -o $@ -g $(PRODUCT_MAIN_OBJ) $(TARGET_LIB) $(EVALUATOR_LIB) $(CPPUTEST_LIB) $(LD_LIBRARIES)
+	@echo 'Build completed. To run the game, execute: ./$(PRODUCT)'
+	@echo 'Then go to your browser to play at http://localhost:8888'

src/html_ui/html_game.c

@@ -7,6 +7,9 @@
 #include "agent.h"
 #include "ui_agent.h"
 
+// Define the global function pointer
+void (*shutdown_server)(void) = NULL;
+
 static int ui_adaptor_pool_add_ui_adaptor(agent_t * ui);
 static agent_t * ui_adaptor_pool_get_ui_adaptor_by_id(int id);
 static void ui_adaptor_pool_remove(int id);

src/html_ui/html_game.h

@@ -9,6 +9,6 @@
 #define HTML_GAME_H_
 
 int execute_game_command(const char * command, const char *parameters, char * buffer, int buffer_size);
-void (*shutdown_server)(void);
+extern void (*shutdown_server)(void);
 
 #endif /* HTML_GAME_H_ */