Add "bluetooth" as an explicit DISTRO_FEATURE and,
as "bluez4" is the default choice, specify "bluez5"
which allows more modern features.
PulseAudio from Poky 1.7 always pulls BlueZ 4 if
Bluetooth is specified, thus creating build errors
unless we add a workaround for it.
Change-Id: I3e9f86c77f5971c0d71666f8decb7d3d3a0fdcb4
Signed-off-by: Manuel Bachmann <mbc@iot.bzh>