ghc-{8.2.2,8.4.1}: fixups mostly for 2-stage cross, musl

* grab patches from gentoo to fix various 2-stage cross build system
  bugs
* explicitly set CrossCompilePrefix to the expected targetPrefix
  -- ensures everything has expected name and location
  -- fixes lack of prefix'ing when doing glibc -> musl "cross"
* Stage1Only: only set if doing "true" cross
* don't try to specify include/lib dirs for ncurses on cross
  -- only used by terminfo which actually removed the include option,
  and the lib option doesn't seem to do anything other than
  confuse the situation re:cross.

Fixes #37522