If folks can reproduce this issue on other platforms than OS X , id greatly appreciate it. If only to confirm that it’s as reproducible as I believe it is. I should mention that at least on OS X, it’s slightly easier to trigger the issue / stumble across it with gcc rather than clang (on OS X, clang was picking up the o stalled system headers but gcc was failing. Without installed headers both fail for me. ) On Mon, Jan 27, 2020 at 10:37 PM Carter Schonwald < carter.schonwald@gmail.com> wrote:

Hey all, For those using Hadrian for platforms where intree gmp config is important, some sleuthing I’ve done over the past half seems to indicate that currently it’s not correct via Hadrian, but only via make.

https://gitlab.haskell.org/ghc/ghc/issues/17756 I’m able to reproduce this on multiple OS X machines (though it took me a while to read apart that is Hadrian specific.)

Punchline : at the moment, Hadrian intree gmp builds succeed because gmp headers in default include search paths of gcc/clang get picked up. In a properly isolated environment / one without the offending header leakage, I’m able at least on OS X to get Hadrian with intree gmp to consistently fail.