add opengl

Makefile

@@ -7,9 +7,9 @@ CXX := $(PREFIX)-g++
 LD := $(PREFIX)-ld
 CPPFLAGS := -I$(SFML_DIR)/include
 CXXFLAGS := -mwindows
-LDFLAGS := -L$(SFML_DIR)/lib -lsfml-system -lsfml-window -static-libstdc++ -static-libgcc -mwindows
+LDFLAGS := -L$(SFML_DIR)/lib -lsfml-system -lsfml-window -lopengl32 -lglu32 -static-libstdc++ -static-libgcc -mwindows
 
-all: clock window events dlls
+all: clock window events opengl dlls
 
 %: %.cpp
 	$(CXX) -o $@ $(CPPFLAGS) $(CXXFLAGS) $^ $(LDFLAGS)