cairo: explicitly disable valgrind

Make our builds slightly more deterministic.

Signed-off-by: Christopher Larson <kergoth@gmail.com>
mel: mask out the meta-virtualization python bbappend

The patch it applies is upstream in oe-core now.

Signed-off-by: Christopher Larson <kergoth@gmail.com>
qemu: add version 1.5.3 to work around native ICE

Signed-off-by: Christopher Larson <kergoth@gmail.com>