[mythtv] Problems with dynamic_cast

[Mark Spieth]

I have another instrumented test if someone can test it. Otherwise it 
will have to wait for approx 7 hours when I get home.

http://digivation.com.au/debian/mythfrontend-20200129-arm64-v31-Pre-1828-g4b2272287a-dirty.apk

use adb logcat | tee x.log

The test is

settings -> video -> playback -> change profile to something else

Then email me with the last bit of the log where it mentions dce especially.

Mark