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
GetDomainSpecs__8DmPolicy @ 1 NONAME R3UNUSED ; DmPolicy::GetDomainSpecs(void)
Release__8DmPolicyPC13TDmDomainSpec @ 2 NONAME R3UNUSED ; DmPolicy::Release(TDmDomainSpec const *)
GetPolicy__8DmPolicyR18TDmHierarchyPolicy @ 3 NONAME R3UNUSED ; DmPolicy::GetPolicy(TDmHierarchyPolicy &)