Fight the compilers. Adore the vanished ugliness. Make sure the delete is in place and no leak snuck in.
Ways to reduce the number of `GUItypes.h` inclusions are to be considered, but will probably be easier to manage in an independent patch.
Brief mentioning on #0ad-dev on http://irclogs.wildfiregames.com/2019-07/2019-07-30-QuakeNet-%230ad-dev.log
> 21:48 < elexis> Vladislav: also would you agree that AddSetting<CStrW>("sound_released"); is better than AddSetting(GUIST_CStrW, "sound_released");?
> 21:49 < Vladislav> elexis: yes, the template one looks more strict.
I've compiled with gcc 9, clang 8.0.1, VS2015, Jenkins.