Add a PACKAGECONFIG for profile-guided-optimisation, and default to whether
qemu-usermode is available.
Move --enable-optimizations to the pgo optimisation as all this currently does
is use the PGO rules, causing a performance hit if PGO isn't actually used.
(From OE-Core rev: 231e13c76d3ca7beebfbc8d8a856f72fa3780601)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>