Intel has optimized the xgboost in latest version. Performance has
obvious acceleration in benchmark. In svm training with Yahoo LTR data,
latest version gets 7.8X acceleration in host, and 2X acceleration in occlum.
Signed-off-by: yuanwu <yuan.wu@intel.com>
Some demos based on CMake may search installed packages out of
Occlum toolchain's directory, this could cause some building
errors sometimes. By setting the $PKG_CONFIG_LIBDIR, we can make
CMake searching for packages in Occlum toolchain's directory only.
