Fix Python – error: command ‘gcc’ failed with exit status 1 while installing eventlet

I wanted to install eventlet on my system in order to have “Herd” for software deployment.. but the terminal is showing a gcc error:
root@agrover-OptiPlex-780:~# easy_install -U eventlet
Searching for eventlet
Reading http://pypi.python.org/simple/eventlet/
Reading http://wiki.secondlife.com/wiki/Eventlet
Reading http://eventlet.net
B….