Makefile - using variables and automatically running programs

In this Makefile I've started using variables in preparation for my next update when I compile each source file separately.

I've also added the command './a.out' so that my unit tests run automatically at the end.

CXXFLAGS = -g -Wall -D_REENTRANT

LIBS  = -lGL \
    -lboost_unit_test_framework \
    -lboost_serialization

INCPATH  = -Iapp \
    -Icritter \
    -Ienvironment \
    -Igraphics \
    -Iui \
    -Iutils \
      -I/usr/local/Trolltech/Qt-4.4.3/include/QtCore \
      -I/usr/local/Trolltech/Qt-4.4.3/include/QtGui \
      -I/usr/local/Trolltech/Qt-4.4.3/include/QtOpenGL \
    -I/usr/local/Trolltech/Qt-4.4.3/include \
    -I/usr/include/GL

all :
 g++  $(CXXFLAGS) \
      test/TestGenome.cpp \
      critter/brain.cp \
      critter/BrainParam.cp \
      utils/misc.cp \
      critter/genome.cp \
      $(LIBS) \
      $(INCPATH)
 ./a.out