build 8.8.1 with 8.8.1 fails with -DSTAGE=1

Summary

ghc-8.8.1 fails to build self, because with -DSTAGE=1 it can't get TAG_MASK from MachDeps.h

(ghc-8.6.3 works, but just because it doesn't pass the -DSTAGE=1 to gcc.)

Steps to reproduce

Build and install 8.8.1. Use it to build 8.8.1 again from scratch.

Expected behavior

Die on stage 1, compiler/parser/cutils.c TAG_MASK undefined in ClosureMacros.h

(I don't really expect that, since I'm sure this has been done numerous times with no problem, but it's what happened here, and the way it works - only 8.8.1 passes -Xpreprocessor '-DSTAGE=1' to gcc - has me quite baffled.)

Related to issue #16797 (closed)

Environment

8.8.1

Optional:

Haiku Intel

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information