/tmp/ccWB3uMn.o: In function `main':
foo.cc:(.text.startup+0x122): undefined reference to `SeqList::Merge()'
foo.cc:(.text.startup+0x12f): undefined reference to `SeqList::Merge()'
foo.cc:(.text.startup+0x137): undefined reference to `SeqList::Merge()'
collect2: error: ld returned 1 exit status