Further update for the extern "C" declarations.
Further update for the extern "C" declarations.

This patch wraps the routine declarations, etc. in an extern "C" block
instead of giving the individual routines an extern "C" definition.

themperek/iverilog,CastMi/iverilog,CastMi/iverilog,CastMi/iverilog,themperek/iverilog,themperek/iverilog