Thanks for Mike Westerhof <mwester@dls.net>

Thanks for  Mike Westerhof <mwester@dls.net>
----------
 This patchset updates the libbb stuff to use a vfork() version of
 gz_open, called gzvopen.  This is done because a standard fork will
 duplicate the entire address space.  This will invoke the OOM
 (out of memory) killer on small-memory machines, because most often
 by the time we unzip any package, we've read the entire package
 database into memory already.  By using vfork() and immediatly
 execing the external gunzip utility, we avoid the need to clone the
 entire address space.

 Yes, this is actually **LESS** efficient than the original way!
 But there is no way to (currently) dodge the OOM killer on a
 per-process basis, so the alternatives are to either change the
 OOM killer behavior system-wide, or to use this workaround.

 Mike Westerhof, Dec 2008

git-svn-id: http://opkg.googlecode.com/svn/trunk@190 e8e0d7a0-c8d9-11dd-a880-a1081c7ac358