CMake/Modules/Platform/FreeBSD.cmake

IF(EXISTS /usr/include/dlfcn.h)
  SET(CMAKE_DL_LIBS "")
  SET(CMAKE_SHARED_LIBRARY_C_FLAGS "-fPIC")            # -pic 
  SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-shared")       # -shared
  SET(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")         # +s, flag for exe link to use shared lib
  SET(CMAKE_SHARED_LIBRARY_RUNTIME_C_FLAG "-Wl,-rpath,")       # -rpath
  SET(CMAKE_SHARED_LIBRARY_RUNTIME_C_FLAG_SEP ":")   # : or empty
ENDIF(EXISTS /usr/include/dlfcn.h)
# include the gcc flags