AFAIK it isn't removed, but it is no longer developed and requires GHC to be in unregistered mode, which most people's won't be. But I could simply be behind the times.

Looking into it, we're both right, in a way:

  > This is the oldest code generator in GHC and is generally not included any
  > more having been deprecated around GHC 7.0. Select it with the -fvia-C flag. 

So it was deprecated, just never removed.