Disabling optimisations for limited subprojects

[mitchgrout]

As I understand, meson setup -Doptimization=3 is a global option, so any subprojects I may have will also be compiled at -O3. I would like to disable this for certain subprojects; what would be the cleanest way of doing this?

One option is to add a <lang>_args=['-O3'] to my build targets, but this would only compile my project at -O3, and leave all my subprojects at the default optimization level.

[vvainola]

Would be nice to have this other way around as well that subprojects have optimizations enabled and main project is without optimizations. Currently adding -Dsubproject:optimization=3 in setup prints it out as changed but it does nothing. Also in VS backend using override_options to change optimization level does not work either.