Good example, this one helped me to understand the plugin function better.
I added the note about changing qmake to qmake-qt4. I found this on another page about making mythtv itself. Maybe I shouldn't have yet - I haven't been able to get everything to make, I need to update some other packages first.
Code change between 0.26 and 0.27
This commit made several changes to the plugin code
For HelloMyth, this means a line is changed and an additional include is needed.
I have Ubuntu 14.04 with Mythbuntu repositories for 0.27 setup. I had to do a git clone of the 0.27 branch with
git clone https://github.com/MythTV/mythtv.git -b fixes/0.27 --single-branch mythtv/
Ran the configure script with ./configure --prefix=/usr
Then did the build and install, the plugin works.
Added ccache and git development requirements
Need git of course. The build fails without ccache.
Added list of packages required to build existing plugins
I have been playing with xubuntu in Virtual Box in order to construct a lightweight build environment, and found many of the existing plugins require additional packages.