How do I rebuild GHC after updating or changing it?

Note that after pulling new changes, the safest way to continue working is to clean the build tree and start from scratch.

In fact, it's best to clean the tree before pulling, because the new code may not know how to clean the old build tree:

  $ make distclean

Now you can sh darcs-all pull, followed by building the tree as normal:

  $ sh boot
  $ ./configure
  $ make

You may be able to shortcut this procedure if you know what you're doing, or you could just take a risk and if anything goes wrong fall back to the above procedure.