bug#10312: lockfile method broken

[Peter O'Gorman]

So I don't forget:

Got a report of installed libtool failing on darwin because the libtool 
script being used was installed on a different device than the builddir, 
so ln "$progpath" "$lockfile" (for the lock for extracting an archive) 
will never work.

Need to:
1) Not lock on modern mac os x, ar no longer takes a lock on the archive 
when reading, this was fixed in Xcode-3.2.2.
2) Lock differently so that cross-device ln isn't involved.

Reported by Peter Dyballa and Martin Costabel here:

http://article.gmane.org/gmane.os.apple.fink.general/33965

Peter