missing "rlm_perl.so" in the built from src file

Hi, I built a fresh freeradius on a ubuntu server from source files. When I add perl module and start the freeradiusin the debug mode, it is asking for "rlm_perl.so" that can not find it. It seems the make file does not create the shared lib file for perl module. Is there any change should be made in Makefile to create "rlm_perl.so" file? Thanks, ASM