CPP definitions from `.cabal` file not picked up

[DigitalBrains1]

clash-prelude.cabal contains:

Library

  -- See https://github.com/clash-lang/clash-compiler/pull/2511
  if impl(ghc >= 9.4)
    CPP-Options: -DCLASH_OPAQUE=OPAQUE
  else
    CPP-Options: -DCLASH_OPAQUE=NOINLINE

But the doctests output a lot of these:

/builds/clash-lang/clash-compiler/clash-prelude/src/Clash/Magic.hs:51:1: warning: [-Wunrecognised-pragmas]
198    Unrecognised pragma
199   |
20051 | {-# CLASH_OPAQUE prefixName #-}
201   | ^^^

doctest picks some things up from the .cabal file but it's very limited. It would be nice if it could pick this up as well. If this is hard to do, a simple command-line argument to doctest would also suffice; we could always pass that argument to mainFromCabal.

[martijnbastiaan]

Thanks for the report! I've implemented and merged support for --ghc-arg, though I do intend to fix this issue properly too.

See: #72

[martijnbastiaan]

Fixed properly in #73.

[martijnbastiaan]

Also see: #75.