makefile.in seems to miss sim.o

Hi, 
thank you for your work which helped me a lot, but I encountered a small problem. The configure and make went fine for my tested platforms, but to compile the test, the sim.o had to be added to the libs in the makefile. 
So I suggest to just add the sim.o in the makefile.in, what solved the small problem for me at least.
Thank you for your time and work.