Handle dlsym(NULL, ...) properly, by searching in the caller's shared object.  Note, this searches _only_ that object, and not its needed objects, in accordance with the documentation.
Handle dlsym(NULL, ...) properly, by searching in the caller's
shared object.  Note, this searches _only_ that object, and not its
needed objects, in accordance with the documentation.

Also fix dlopen(NULL, ...) so that the executable's needed objects
are searched as well as the executable itself.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase