Add variant support to command line interface and job sets.

For the moment this does not include netlist support because the board
editor does not support handling variants.  This means that the Python
script BOM generation cannot be used for variants.

kicad/cli/command_sch_export_plot.cpp

@@ -55,6 +55,7 @@ CLI::SCH_EXPORT_PLOT_COMMAND::SCH_EXPORT_PLOT_COMMAND( const std::string& aName,
     addCommonArgs( true, true, false, aOutputIsDir );
     addDrawingSheetArg();
     addDefineArg();
+    addVariantsArg();
 
     m_argParser.add_argument( "-t", ARG_THEME )
             .default_value( std::string() )
@@ -190,6 +191,7 @@ int CLI::SCH_EXPORT_PLOT_COMMAND::doPerform( KIWAY& aKiway )
         plotJob->m_PDFMetadata = !m_argParser.get<bool>( ARG_EXCLUDE_PDF_METADATA );
     }
 
+    plotJob->m_variant = From_UTF8( m_argParser.get<std::string>( ARG_VARIANT ).c_str() );
     int exitCode = aKiway.ProcessJob( KIWAY::FACE_SCH, plotJob.get() );
 
     return exitCode;