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
CreateLogicalDevice__Fv @ 1 NONAME R3UNUSED ; CreateLogicalDevice(void)
ExportMultiplyFunction__FUiUi @ 2 NONAME R3UNUSED ; ExportMultiplyFunction(unsigned int, unsigned int)