Install XEN on ubuntu

 Download XEN 3.3.1 and compile from source. An error occurred.

make[3]: *** [linux-2.6.18-xen.hg/.valid-src] Error 127

You need to download mercurial   http://www.selenic.com/mercurial/wiki/index.cgi/BinaryPackages

# apt-get install mercurial

It takes such a long time to add file changes. I do not know why. It seems a Linux kernel is downloaded. 

check_xgettext FAILED: can't find xgettext
 apt-get install gettext   there is no 'x' Remember it! The result is  find /usr/ -name *xgettext -print

/usr/bin/xgettext.

I made a serious mistake. I typed command 'make world' and all of these compiled files had been deleted. All of my work had to begin from zero. The most boring thing is that it began to download the kernel again and this might take more than an hour. The previous kernel had been deleted. Next time if some error occurred during compile time, just type 'make dist',it is very important.

check_x11_devel FAILED: can't find X11 headers  apt-get install libghc6-x11-dev