Hadrian passes -rtsopts when building libraries

Hadrian shows many warnings of the form

Warning: -rtsopts and -with-rtsopts have no effect with -shared.
    Call hs_init_ghc() from your main() function to set these options.

while building ghc.

I believe this is because of the line

            , not (nonHsMainPackage pkg) ? arg "-rtsopts"

in hadrian/src/Settings/Builders/Ghc.hs