`ghc` in `pkg` is incapable of bootstrapping

[raichoo]

Hi,

I've posted on this list a couple of weeks ago. GHC 8.4.1+ has enabled
dtrace probes on
FreeBSD, sadly this caused an issue with GHC's ability to function as a
bootstrap compiler to
build GHC. 8.4.2 added a flag to disable dtrace support and link the RTS in
a way that
does not tamper with the bootstrap ability of the compiler.

I'd recommand to ship GHC built with --disable-dtrace for the moment. That
does not seem to
be the case with the GHC that is currently being shipped via `pkg` so
people trying
to bootstrap their own compiler might run into unpleasant surprises.

I've just now submitted a patch to GHC project that fixes this issue and
it'll hopefully be
available as soon as possible.

Kind regards,
raichoo