Thank you for responding.
Yes(I wish I had not mistaken the command.......:smileycry:).
I used gonme-shell and executed commands as follows.
$ sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat cpio python python3 python3-pip python3-pexpect xz-utils debianutils iputils-ping
$ sudo apt-get install libsdl1.2-dev xterm sed cvs subversion coreutils texi2html docbook-utils python-pysqlite2 help2man make gcc g++ desktop-file-utils libgl1-mesa-dev libglu1-mesa-dev mercurial autoconf automake groff curl lzop asciidoc
$ sudo apt-get install libsdl1.2-dev xterm
$ sudo apt-get install make xsltproc docbook-utils fop dblatex xmlto
$ sudo apt-get install python-git
$ chmod u+x x86_64-buildtools-nativesdk-standalone-2.6.1.sh
$ ./x86_64-buildtools-nativesdk-standalone-2.6.1.sh
$ sudo apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib build-essential chrpath socat libsdl1.2-dev
$ mkdir ~/bin
$ chmod a+x ~/bin/repo
$ export PATH=~/bin:$PATH
$ git config --global user.name "****************"
$ git config --global user.email "****************@**************"
$ git config --list
$ mkdir imx-yocto-bsp
$ cd imx-yocto-bsp
$ repo sync
$ DISTRO=fsl-imx-xwayland MACHINE=imx8mqevk source fsl-setup-release.sh -b build-xwayland
$ bitbake fsl-image-qt5-validation-imx