Unity game crashes with 0xc06d007e (FlsGetValue2 not found in kernelbase.dll) on both stable and beta engines

[je1001dev]

Environment

• Whisky 3.7.0, macOS 26.0.0, Apple M5
• Bottle: Windows 10, Wine 11.0 (stock v3.1.1 engine) — also reproduced on v4.6.4-beta.1 (Wine 11.16)

Game
"How to Fish" (Steam AppID 4001890), a Unity engine game.

Symptom
The game crashes immediately with Unhandled exception 0xc06d007e at the exact same address (kernelbase+0xd887) regardless of graphics backend (DXVK/D3D11 fully initializes — device, swapchain, DXGI format conversion all succeed — before the crash occurs, so this is not a graphics API issue).

Root cause found

warn:module:LdrGetProcedureAddress "FlsGetValue2" (ordinal 0) not found in "kernelbase.dll"

kernelbase.dll only exports FlsGetValue / RtlFlsGetValue, not FlsGetValue2. Confirmed via strings on both the stock (wine-11.0) and beta (wine-11.16) kernelbase.dll — neither has this export. The Unity engine's runtime (likely via a newer UCRT build) delay-loads this symbol during early bootstrap and crashes when it's missing.

Backtrace (relevant frames)

=>0 kernelbase (+0xd887)
  1-10 unityplayer (+0x1c35223, +0x1bc6397, +0x103e233, +0x10a8960, +0xfb696b, +0x12c0266, +0x13e6c0c, +0x13b0bac, +0x11c2877, +0x11c2fbb)
  11 how to fish (+0x11f6)
  12 kernel32 (+0x11469)
  13 ntdll (+0x10d2b)

Ask
Could FlsGetValue2 be added to kernelbase.dll (likely a thin wrapper around the existing FLS implementation)? Happy to test a beta build.