libatomic-ops: Add BBCLASSEXTEND for native (to support bdwgc-native)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
serf: Add new recipe (needed by subversion for http support)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
subversion: neon support was dropped, switch to serf

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