https://bugs.winehq.org/show_bug.cgi?id=49577
--- Comment #3 from Paul Gofman pgofman@codeweavers.com --- (In reply to Béla Gyebrószki from comment #2)
How do I check for those leftover .so binaries?
I would suggest deleting the build directory completely before doing a build and build everything from scratch in such case (unless you did that already). If you are building in the source directory git clean -d -f -x has done that already (but I always build in a separate).
Would it help if I narrowed down the problem to a specific Staging commit between 5.11 and 5.12.1 or that would be only a red herring?
Might be, yes, depending on what commit is it. But if it is, e. g., some flavour of DLL size issue like we had lately that won't tell much.
Maybe you can try to run wine from gdb? backtrace is unlikely to show anything but if we get a segfault address and you can send me the crashing binary from your build it could be a good start.