If '/etc/ld.so.cache' does not contain any old entries
using the 'HeaderOld' struct then it fails with a bad-magic
error before looking for the HeaderNew entries.
My Ubuntu 19.10 system doesn't have any old entries so always
fails here when using 'load-all', which results in the
'extra/llvm' vocab failing due to using 'find-so'.
The fix implemented here is to catch the error and recover from
it by seeking back to the start of the header before looking for
the new header entries.
Chris Double
Doug Coleman
Björn Lindqvist