Honour the flavours advertised by the flavours.md document (Trac #691)
- honour the flavours advertised by our flavours.md document
In particular, this patches focuses on enabling back the dynamic-enabled ways
for the runtime system, which required to fix a bug in libsuf.
- address some feedback
- make dynamicGhcPrograms :: Action Bool to implement the default logic faithfully
- remove redundant windows check