undefined reference to 'xxx' 에 대해 질문드립니다. ㅎ

#----------------------------------------------------------------------
# From the list below, please activate/deactivate the options that     
# apply to your run. If you modify any of these options, make sure     
# that you recompile the whole code by typing "make clean; make".      
#                                                                      
# Look at end of file for a brief guide to the compile-time options.   
#----------------------------------------------------------------------
 
 
#--------------------------------------- Basic operation mode of code
#OPT   +=  -DPERIODIC 
OPT   +=  -DUNEQUALSOFTENINGS
 
 
#--------------------------------------- Things that are always recommended
OPT   +=  -DPEANOHILBERT
OPT   +=  -DWALLCLOCK   
 
 
#--------------------------------------- TreePM Options
#OPT   +=  -DPMGRID=128
#OPT   +=  -DPLACEHIGHRESREGION=3
#OPT   +=  -DENLARGEREGION=1.2
#OPT   +=  -DASMTH=1.25
#OPT   +=  -DRCUT=4.5
 
 
#--------------------------------------- Single/Double Precision
#OPT   +=  -DDOUBLEPRECISION      
#OPT   +=  -DDOUBLEPRECISION_FFTW      
 
 
#--------------------------------------- Time integration options
OPT   +=  -DSYNCHRONIZATION
#OPT   +=  -DFLEXSTEPS
#OPT   +=  -DPSEUDOSYMMETRIC
#OPT   +=  -DNOSTOP_WHEN_BELOW_MINTIMESTEP
#OPT   +=  -DNOPMSTEPADJUSTMENT
 
 
#--------------------------------------- Output 
#OPT   +=  -DHAVE_HDF5  
#OPT   +=  -DOUTPUTPOTENTIAL
#OPT   +=  -DOUTPUTACCELERATION
#OPT   +=  -DOUTPUTCHANGEOFENTROPY
#OPT   +=  -DOUTPUTTIMESTEP
 
#--------------------------------------- Things for special behaviour
#OPT   +=  -DNOGRAVITY     
#OPT   +=  -DNOTREERND 
#OPT   +=  -DNOTYPEPREFIX_FFTW        
#OPT   +=  -DLONG_X=60
#OPT   +=  -DLONG_Y=5
#OPT   +=  -DLONG_Z=0.2
#OPT   +=  -DTWODIMS
#OPT   +=  -DSPH_BND_PARTICLES
#OPT   +=  -DNOVISCOSITYLIMITER
#OPT   +=  -DCOMPUTE_POTENTIAL_ENERGY
#OPT   +=  -DLONGIDS
#OPT   +=  -DISOTHERM_EQS
#OPT   +=  -DADAPTIVE_GRAVSOFT_FORGAS
#OPT   +=  -DSELECTIVE_NO_GRAVITY=2+4+8+16
 
#--------------------------------------- Testing and Debugging options
#OPT   +=  -DFORCETEST=0.1
 
 
#--------------------------------------- Glass making
#OPT   +=  -DMAKEGLASS=262144
 
 
#----------------------------------------------------------------------
# Here, select compile environment for the target machine. This may need 
# adjustment, depending on your local system. Follow the examples to add
# additional target platforms, and to get things properly compiled.
#----------------------------------------------------------------------
 
#--------------------------------------- Select some defaults
 
CC       =  mpicc               # sets the C-compiler
FC       =  mpif77
OPTIMIZE =  -O2 -Wall -g        # sets optimization and warning flags
MPICHLIB =  -lmpich
 
 
#--------------------------------------- Select target computer
 
SYSTYPE="MPA"
#SYSTYPE="Mako"
#SYSTYPE="Regatta"
#SYSTYPE="RZG_LinuxCluster"
#SYSTYPE="RZG_LinuxCluster-gcc"
#SYSTYPE="OpteronMPA"
#SYSTYPE="OPA-Cluster32"
#SYSTYPE="OPA-Cluster64"
 
 
#--------------------------------------- Adjust settings for target computer
 
ifeq ($(SYSTYPE),"MPA")
CC       =  mpicc
FC       =  mpif77
OPTIMIZE =  -O3 -Wall
GSL_INCL =  -I/home/kwchun/gsl/include
GSL_LIBS =  -L/home/kwchun/gsl/lib  #"-R /home/kwchun/gsl/lib"# -Wl,"-R /home/myjeon/gadget2/usr/lib"
FFTW_LIBS = -L/home/kwchun/fftw/lib
FFTW_INCL = -I/home/kwchun/fftw/include
MPICHLIB =  -L/mpich2-install/lib
HDF5INCL =  -I/home/kwchun/hdf5/include
HDF5LIB  =  -L/home/kwchun/hdf5/lib
endif
 
OPTIONS =  $(OPTIMIZE) $(OPT)
 
EXEC   = Gadget2
 
OBJS   = main.o  run.o  predict.o begrun.o endrun.o global.o  \
         timestep_cool.o  init.o restart.o  io.o    \
         accel.o   read_ic.o  ngb.o  \
         system.o  allocate.o  density.o  \
         gravtree.o hydra_cool.o  driftfac.o  \
         domain.o  allvars.o potential.o  \
         forcetree.o   peano.o gravtree_forcetest.o \
         pm_periodic.o pm_nonperiodic.o longrange.o \
         external_force.o nrutil.o cooling.o get_lambda.o
 
 
INCL   = allvars.h  proto.h  tags.h  external_force.h nrutil.h mpif.h header.h cooling.h Makefile
 
 
CFLAGS = $(OPTIONS) $(GSL_INCL) $(FFTW_INCL) $(HDF5INCL)
 
FCFLAGS = $(OPTIONS) $(GSL_INCL) $(FFTW_INCL) $(HDF5INCL)
 
ifeq (NOTYPEPREFIX_FFTW,$(findstring NOTYPEPREFIX_FFTW,$(OPT)))    # fftw installed with type prefix?
  FFTW_LIB = $(FFTW_LIBS) -lrfftw_mpi -lfftw_mpi -lrfftw -lfftw
else
ifeq (DOUBLEPRECISION_FFTW,$(findstring DOUBLEPRECISION_FFTW,$(OPT)))
  FFTW_LIB = $(FFTW_LIBS) -ldrfftw_mpi -ldfftw_mpi -ldrfftw -ldfftw
else
  FFTW_LIB = $(FFTW_LIBS) -lsrfftw_mpi -lsfftw_mpi -lsrfftw -lsfftw
endif
endif
 
 
LIBS   =  $(HDF5LIB) -g  $(MPICHLIB)  $(GSL_LIBS) -lgsl -lgslcblas -lm $(FFTW_LIB)
 
 
$(EXEC): $(OBJS)
        $(FC) $(OBJS) $(LIBS) -o $(EXEC)
 
 
$(OBJS): $(INCL)
 
 
clean:
        rm -f $(OBJS) $(EXEC)