Makefile - incremental compilation

The big change from the last Makefile is that I am now separating my compiling so that only things that change get recompiled.

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 : TestGenome.o brain.o BrainParam.o misc.o genome.o
 g++  $(CXXFLAGS) \
      TestGenome.o \
      brain.o \
      BrainParam.o \
      misc.o \
      genome.o \
      $(LIBS) \
      $(INCPATH)
 ./a.out

TestGenome.o: test/TestGenome.cpp
 g++ -c $(CXXFLAGS) test/TestGenome.cpp $(INCPATH)

brain.o: critter/brain.cp critter/brain.h
 g++ -c $(CXXFLAGS) critter/brain.cp $(INCPATH)

BrainParam.o: critter/BrainParam.cp critter/BrainParam.h
 g++ -c $(CXXFLAGS) critter/BrainParam.cp $(INCPATH)

misc.o: utils/misc.cp utils/misc.h
 g++ -c $(CXXFLAGS) utils/misc.cp $(INCPATH)

genome.o: critter/genome.cp critter/genome.h
 g++ -c $(CXXFLAGS) critter/genome.cp $(INCPATH)

If you look at the line beginning with 'brain.o:' you'll see that it is followed by 'critter/brain.cp' and 'critter/brain.h'. This specifies that if 'critter/brain.cp' or 'critter/brain.h' changes, then brain.o should be recompiled.

Though this is useful, there are still problems with dependencies. For example, what if 'critter/brain.h' refers to another header file that has changed? I'm not sure but I'll follow up on that soon.