I just tried to compile Factory package openbabel-2.2.0-4.81
and the compiler said

1.

ichirvr2.c:239: warning: operation on 'jn' may be undefined

The source code is

           at[jn = at[n_vertex].neighbor[1]].valence + at[jn].num_H == 3 &&

I agree with the compiler, the code is undefined.
Suggest code rework. Perhaps

           ((jn = at[n_vertex].neighbor[1]]),
                (at[ jn].valence + at[jn].num_H)) == 3 &&

would work.

2.

cl_list.c:496: warning: operation on 'item_count' may be undefined

similar.