cmake/meson inconsistent soversion with 1.8.4

[userwithuid]

meson.build uses 20
CMakeLists.txt uses 19

[cdunn2001]

This will probably happen again. Could you help us to include a single soversion into both?

[baylesj]

Added some comments to hopefully avoid this in future releases.

[dota17]

Closing. seems like this has been resolved.