image_types.bbclass: only create links if the target exists

When creating images containing many partitions, rootfs.$type
may not be available.

Signed-off-by: Andreas Oberritter <obi@opendreambox.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
tcltk: Fix for ${B} != ${S}

This change allows ${B} != ${S} builds to work since otherwise
gnu-configise is executed in the wrong places and various source
paths aren't correct.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
package: Add cachedpath optimisation

Currently, various standard library operations like os.walk(),
os.path.isdir() and os.path.islink() each call stat or lstat which
involves a syscall into the kernel. There is no caching since they could
conceivably have changed on disk. The result is that for something like
the do_package task of the kernel we're spending over two minutes making
868,000 individual stat calls for 23,000 files. This is suboptimal.

This patch adds lib/oe/cachedpath.py which are a set of replacement
functions for these operations which use cached stat data rather than
hitting the kernel each time. It gives a nice performance improvement
halving the build time of the kernel do_package.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
zaurusd: Update to new git version

Makefile fix (patch) was merged upsream
Out of tree builds were also fixed

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>