Invoker callback_param() now handles nil values for callback params, which equates to a NULL function pointer in C.
Invoker callback_param() now handles nil values for callback params, which equates to a NULL function pointer in C.

sparkchaser/ffi,ffi/ffi,majioa/ffi,majioa/ffi,yghannam/ffi,yghannam/ffi,majioa/ffi,yghannam/ffi,mvz/ffi,MikaelSmith/ffi,tduehr/ffi,ferventcoder/ffi,mvz/ffi,MikaelSmith/ffi,MikaelSmith/ffi,ffi/ffi,yghannam/ffi,tduehr/ffi,sparkchaser/ffi,tduehr/ffi,ffi/ffi,tduehr/ffi,mvz/ffi,majioa/ffi,ferventcoder/ffi,sparkchaser/ffi,sparkchaser/ffi,ferventcoder/ffi,ferventcoder/ffi,mvz/ffi,MikaelSmith/ffi,yghannam/ffi