The type or namespace name ‘Reporting’ does not exist in the namespace ‘Microsoft’

In my case I needed to actually install Microsoft Report Viewer on the troublesome machine.

• Report Viewer 2010 (version=10)
• Report Viewer 2012 (version=11)
• Report Viewer 2015

Of course, other ones are available, it can be worked out which from the Version= on the dll which one is needed. In my case I needed version 11 (the 2012 one).