Building OS for colibri VF61 module using Yocto project

Dear Sir,

I am building OS for Colibri VF61 module, I have Colibri VF61 Ver1.2B module and Colibri Evaluation board.
Development System Ubuntu 18.04

I am following below link to build yocto image for VF61.

I am stuck at bitbake core-image-safo

rahulk@rahulk-ThinkCentre-E73:~/Toradex_yocto/poky/build$ bitbake core-image-safo
WARNING: Host distribution “Ubuntu-18.04” has not been validated with this version of the build system; you may possibly experience unexpected failures. It is recommended that you use a tested distribution.
ERROR: OE-core’s config sanity checker detected a potential misconfiguration.
Either fix the cause of this error or at your own risk disable the checker (see sanity.conf).
Following is the list of potential problems / advisories:

Please set a valid MACHINE in your local.conf or environment

Please install the following missing utilities: makeinfo,gawk,chrpath

Summary: There was 1 WARNING message shown.
Summary: There was 1 ERROR message shown, returning a non-zero exit code.

I added MACHINE?= “colbri-vf” in conf/local.conf as follows.

#MACHINE ?= “beaglebone”
#MACHINE ?= “genericx86”
#MACHINE ?= “genericx86-64”
#MACHINE ?= “mpc8315e-rdb”
#MACHINE ?= “edgerouter”

This sets the default machine to be qemux86 if no other machine is selected:

#MACHINE ??= “qemux86”
MACHINE ?= “colibri-vf”

but still unable to build OS. Please can you help me out.

Rahul K.

Why “core-image-safo”? You should build angstrom-lxde-image for Colibri VF61