Modules behind compiler flags aren't shown

[Vlix]

Unlike hackage, where password's haddock is built and shown in the module tree, on stackage, the modules aren't shown.

These modules are "behind" compiler flags, but they are enabled by default, and like on hackage should be shown.

[andreasabel]

stack haddock also shows all modules.

[bergmark]

It could be that that the flags need to be specified in the package-flags section in build-constraints even if they have a default. If so, I'm not sure what the reason is, certainly unexpected behavior.