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
_Z16KeyDataConvTableR10SConvTableRjS1_R18SScanCodeBlockListR12SKeyCodeList @ 1 NONAME ; KeyDataConvTable(SConvTable&, unsigned int&, unsigned int&, SScanCodeBlockList&, SKeyCodeList&)
_Z16KeyDataFuncTableR11SFuncTables @ 2 NONAME ; KeyDataFuncTable(SFuncTables&)
_Z15KeyDataSettingsR6TRadixR22TCtrlDigitsTerminationRiS3_ @ 3 NONAME ; KeyDataSettings(TRadix&, TCtrlDigitsTermination&, int&, int&)