core: fails to compile on win32

[hordurj]

Build fails on win32 after PR1254 and later.

On win32/d3d12 sprite example fails on frame 2048.
Following error is reported to the debug view.
[38812] D3D12: Removing Device.
[38812] D3D12 ERROR: ID3D12Device::RemoveDevice: Device removal has been triggered for the following reason (DXGI_ERROR_DEVICE_HUNG: The Device took an unreasonable amount of time to execute its commands, or the hardware crashed/hung. As a result, the TDR (Timeout Detection and Recovery) mechanism has been triggered. The current Device Context was executing commands when the hang occurred. The application may want to respawn and fallback to less aggressive use of the display hardware). [ EXECUTION ERROR #232: DEVICE_REMOVAL_PROCESS_AT_FAULT]

This error does not occur if vsync is enabled.
It does not occur when compiled with -Doptimized=ReleaseFast

This might indicate there is some race condition causing memory corruption.
It starts failing on this commit 984d4de

[slimsag]

Temporary fix merged, filed #1259 and #1260 as follow ups