I have a design that uses imported C functions, and they depend on dynamic libraries, which therefore needs -l flags to be passed to the linker. When I tried using BSC to generate a Verilator simulation executable (with bsc -vsim verilator -e), Verilator failed with errors about missing references, because it was not including those libraries. I discovered that the bsc_build_vsim_verilator script wasn't passing those linker flags to Verilator.

I patched the script to pass BSC_C_LIB_PATH, BSC_CLINK_OPTS, and BSC_C_LIBS as LDFLAGS. This fixed my situation, although I was only using BSC_C_LIBS, so I haven't tested on an example that has the other two kinds of flags.