HelpSource: Internal Snooping - remove macism and obsolete functionality

Signed-off-by: Tim Blechmann <tim@klingt.org>
include: sclang - SC_TerminalClient is not in the public interface

the SC_TerminalClient is used by the sclang command line application,
it does not need to be exposed to the public

Signed-off-by: Tim Blechmann <tim@klingt.org>