I have a parallel program that requires "make" command to compile many source files. I use this "make all" command but get these messages:

/usr/bin/ld: cannot find -lX11
collect2: ld returned 1 exit status
gmake[1]: *** [../bin/paradis] Error 1

I cannot figure out what's wrong with my program and make files. Can anyone help me? Thank you.

More of the message is as follows:

Timer.o Topology.o TrapezoidIntegrator.o Util.o WriteArms.o WriteBinaryRestart.o WriteDensFlux.o WriteDensityField.o WriteFragments.o WritePoleFig.o WritePovray.o WriteProp.o WriteRestart.o WriteTSB.o WriteVelocity.o DisplayC.o display.o -o ../bin/paradis -L/usr/lib64 -lX11 -lpthread -lm
/usr/bin/ld: cannot find -lX11
collect2: ld returned 1 exit status
gmake[1]: *** [../bin/paradis] Error 1
gmake[1]: Leaving directory `/home/h0337502/parallel/src'
gmake[1]: Entering directory `/home/h0337502/parallel/src'
g++ CTableGen.o CorrectionTable.o FMSigma2.o FMSupport.o Heap.o MemCheck.o QueueOps.o Util.o -o ../bin/ctablegenp -L/usr/lib64 -lX11 -lpthread -lm
/usr/bin/ld: cannot find -lX11
collect2: ld returned 1 exit status
gmake[1]: *** [../bin/ctablegenp] Error 1
gmake[1]: Leaving directory `/home/h0337502/parallel/src'