How do I link Allegro 5 from my Makefile?

I need 开发者_JS百科to link the Allegro Game Development Library from my Makefile. When I do this, the compiler returns:

Undefinied Reference < Function Name >.

Before trying to embed the compilation line into the Makefile, make sure you understand how to do it the command line, and more important, make sure it works:

g++ hello.cpp -o hello -I/usr/include/allegro5 -L/usr/lib -lallegro

Then, a simple Makefile to compile hello.cpp could be:

CXX=g++
CFLAGS=
LDFLAGS=-L/usr/lib -lallegro
INCLUDE=-I. -I/usr/include/allegro5

OBJS=hello.o
OUT=hello

all: hello_rule

clean:
        rm -rf *.o hello

hello_rule: $(OBJS)
        $(CXX) $(OBJS) -o $(OUT) $(INCLUDE) $(CFLAGS) $(LDFLAGS)