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
?Export1@@YAHXZ @ 1 NONAME ; int __cdecl Export1(void)
?Export2@@YAHXZ @ 2 NONAME ; int __cdecl Export2(void)
?Export3@@YAHXZ @ 3 NONAME ; int __cdecl Export3(void)
?Export4@@YAHXZ @ 4 NONAME ABSENT ; int __cdecl Export4(void)
?Export5@@YAHH@Z @ 5 NONAME ; int __cdecl Export5(int)