Note that anything not listed here is off Austin's radar.
The dynamic story is complex. Here's the breakdown:
-dynamic: makes GHC produce .so/.dll files rather than .o files.
-dynamic-too: strictly an optimization, -dynamic-too allows the compiler to build static and dynamic object files at once. This is convenient for Dynamic GHCi support.
Windows is a bit difficult right now.
Good news: 64bit builds work using the fancy new MSYS2 environment with a few (~6) failures!
Bad news: 32bit builds work well using the old environment
It seems -dynamic is busted, as well as -dynamic-too
Consequently, GHCi can't be dynamically linked.
We're punting all three of them for the RC.
(Related but not immediately critical: we have too many DLL symbols, and are very close to the limit (#5987 (closed)). Linking also takes a long time (#8229 (closed)))