Kbuild: Add support for multiple toolchains

To use this, export the following:

export VXMICRO_GCC_VARIANT=yocto # for yocto
export VXMICRO_GCC_VARIANT=xtools # for crosstool-ng

export YOCTO_SDK_INSTALL_DIR=/opt/poky-tm/1.8
or
export XTOOLS_TOOLCHAIN_PATH=/opt/crosstool-ng

Change-Id: I9cd6062ecc32047d1582aad46209f4232e0e31f6
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
5 files changed