Re: <help-gift>errors when I do make

thanks for your help.
I think the problem is I haven't install the prerequisites properly. I
can't understand the following sentence which was described in README
of prerequisites package.

'Afterwards, for using what you've installed, you will need to run
source env.sh'

I can't find the file "env.sh" either in prequisites's package or
gift's package.
where is it?
Maybe this is a childish quesition,but I can't figure out myself.