Enhance the base/rom extension to generate the symbol file of the rom built.
The symbol file is placed in epoc32/rom/<baseport_name>, along with the rom log and final oby file.
EXPORTS
_Z13IsTraceActiveRK13TTraceContext @ 1 NONAME
_Z8OstPrintRK13TTraceContextRK6TDesC8 @ 2 NONAME
_Z8OstPrintRK13TTraceContextRK7TDesC16 @ 3 NONAME
_Z8OstTraceRK13TTraceContextt @ 4 NONAME
_Z8OstTraceRK13TTraceContexttPKvi @ 5 NONAME
_Z8OstTraceRK13TTraceContexttRK6TDesC8 @ 6 NONAME
_Z8OstTraceRK13TTraceContexttRK7TDesC16 @ 7 NONAME
_Z8OstTraceRK13TTraceContextth @ 8 NONAME
_Z8OstTraceRK13TTraceContexttm @ 9 NONAME
_Z8OstTraceRK13TTraceContexttmm @ 10 NONAME
_Z8OstTraceRK13TTraceContexttt @ 11 NONAME
_Z9OstPrintfRK13TTraceContext11TRefByValueIK6TDesC8Ez @ 12 NONAME
_Z9OstPrintfRK13TTraceContext11TRefByValueIK7TDesC16Ez @ 13 NONAME
_Z9OstPrintfRK13TTraceContextPKcz @ 14 NONAME
_ZN13TTraceContext18DefaultComponentIdEv @ 15 NONAME
_ZNK13TTraceContext11ComponentIdEv @ 16 NONAME
_ZNK13TTraceContext14ClassificationEv @ 17 NONAME
_ZNK13TTraceContext17HasProgramCounterEv @ 18 NONAME
_ZNK13TTraceContext23HasThreadIdentificationEv @ 19 NONAME
_ZNK13TTraceContext7GroupIdEv @ 20 NONAME