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
_Z8thrower2i @ 1 NONAME
_Z8thrower3i @ 2 NONAME
_Z8thrower4i @ 3 NONAME
_Z8thrower5i @ 4 NONAME
_ZN14UncaughtTesterC1ERi @ 5 NONAME
_ZN14UncaughtTesterC2ERi @ 6 NONAME
_ZN14UncaughtTesterD1Ev @ 7 NONAME
_ZN14UncaughtTesterD2Ev @ 8 NONAME
_ZTT17MyFourthException @ 9 ABSENT