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
?GetAddressOfDataProxy@@YAPAPAXAAHAAPAX1@Z @ 1 NONAME ; void * * GetAddressOfDataProxy(int &, void * &, void * &)
?CheckWritableStaticData@@YAHXZ @ 2 NONAME ; void CheckWritablStaticData(void)