Fix for the "extend" command when running with an x86_64 crash binary
that was built with "make target=ARM64" in order to analyze ARM64
dumpfiles on an x86_64 host.  Without the patch, if the extend
command is used with an extension module built in the same manner,
it fails with the message "extend: <module>.so: not an ELF format
object file".
(Jan.Karlsson@sonymobile.com)