complibs/libelf: use target ranlib

For portability, the right ranlib for the target must be passed to
libelf's configure.

Signed-off-by: "Titus von Boxberg" <titus@v9g.de>

 reporter_name="Ioannis E. Venetis"

 reporter_url="http://sourceware.org/ml/crossgcc/2011-05/msg00005.html"

 reporter_comment=""