Headless-server setting in flex-config.xml fixes error on automated build

I came across this error during an automated build on the server:

Error: An error occurred because there is no graphics environment available.  Please set the headless-server setting in the Flex configuration file to true.

This happens when the server isn’t hooked up to a monitor, mouse, keyboard, etc. The flex-config.xml file needs to be updated with this tag to solve this issue:

<headless-server>true</headless-server>

Read more here:
http://livedocs.adobe.com/flex/201/html/wwhelp/wwhimpl/common/html/wwhelp.htm?context=LiveDocs_Book_Parts&file=performance_118_41.html