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
_ZN6DPTest10FlushCacheEv @ 1 NONAME
_ZN6DPTest12SetCacheSizeEjj @ 2 NONAME
_ZN6DPTest9CacheSizeERjS0_S0_ @ 3 NONAME
_ZN6DPTest9EventInfoER5TDes8 @ 4 NONAME
_ZN6DPTest10AttributesEv @ 5 NONAME