--- Comment #1 from R Copley <rcopley at gmail dot com> ---
The recipe isn't as stable as I thought. The same recipe on a different machine
doesn't reproduce the issue. Apologies.
On that machine with a real project (sorry, no minimal example) I'm now seeing
internal error in mingw32_gt_pch_use_address, at
config/i386/host-mingw32.c:186: MapViewOfFileEx: Attempt to access invalid
<command-line>: fatal error: had to relocate PCH
As this is in mingw32-specific code it's probably for them to look at; also
note that the MSYS2 package-build script also has a patch in this area
I tried the obvious experiment of editing the binaries to disable ASLR. Sure
enough, this makes the problem go away. Note though that this didn't change
between 9.1 and 9.2. The MSYS2 binaries for both versions have ASLR enabled.