Make sure variables are initialized before using them

Make sure variables are initialized before using them

In elf.c, do not increment `s' before it is initialized. At the time
of the increment, `s' is otherwise unused anyway.

In elflink.c, initialize sec_contents and l_sec_contents to make
sure that the free(sec_contents) and free(l_sec_contents) are called
on valid pointers.

ok jca@ guenther@