Subject: bug#21281: 25.0.50.1 (getenv "HOSTNAME") fails

From: Glenn Morris <[email-masked]>
Date: Mon, 17 Aug 2015 11:37:01 -0400

You should read about environment variables and shell variables.
This is nothing to do with Emacs.

http://stackoverflow.com/questions/6353065/hostname-set-in-environment-but-not-visible-to-gmake