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
_ZN6MiscHw16PlayBeepSequenceEPKiiPFvPvES2_ @ 1 NONAME ; MiscHw::PlayBeepSequence(int const*, int, void (*)(void*), void*)
_ZN6MiscHw18CancelBeepSequenceEv @ 2 NONAME ; MiscHw::CancelBeepSequence()
_ZN6MiscHw23SetSoundDriverRecordingEi @ 3 NONAME ; MiscHw::SetSoundDriverRecording(int)