Adds the capnproto package. This also builds a host variant to generate
the capnp compiler that can be used to compile message definitions into
C++ code. Includes a patch from upstream to fix an issue with uclibc.
Signed-off-by: Koen Martens <gmc@sonologic.nl>
Signed-off-by: Joel Carlson <JoelsonCarl@gmail.com>
[Thomas: only link with -latomic when BR2_TOOLCHAIN_HAS_LIBATOMIC=y.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>