vulkan: Backport build fix for MinGW-w64 8.0.0

[akien-mga]

Taken from KhronosGroup/Vulkan-Loader#475.

Supersedes and reverts #43119 since the upstream change removes the need for
that custom define.

@fire @Anutrix can you check that this works for you?

[Anutrix]

@akien-mga The patch works for me.
Tested on Windows 10 with MinGW-LLVM stable 10.0.0(https://github.com/mstorsjo/llvm-mingw/releases/tag/20200325).

[Anutrix]

There seems to be a problem. I messed up somewhere. Turns out this fix doesn't work. @akien-mga
I'm sorry for the trouble.
Here's the full error:

[ 42%] �[94mCompiling �[95m==> �[93mthirdparty\vulkan\loader\loader.c�[0m
=====
b"thirdparty\\vulkan\\loader\\loader.c:6046:5: error: use of undeclared identifier 'IDXGIFactory6'\r\n    IDXGIFactory6* dxgi_factory = NULL;\r\n    ^\r\nthirdparty\\vulkan\\loader\\loader.c:6046:20: error: use of undeclared identifier 'dxgi_factory'\r\n    IDXGIFactory6* dxgi_factory = NULL;\r\n                   ^\r\nthirdparty\\vulkan\\loader\\loader.c:6047:42: error: use of undeclared identifier 'IID_IDXGIFactory6'\r\n    HRESULT hres = fpCreateDXGIFactory1(&IID_IDXGIFactory6, &dxgi_factory);\r\n                                         ^\r\nthirdparty\\vulkan\\loader\\loader.c:6047:62: error: use of undeclared identifier 'dxgi_factory'\r\n    HRESULT hres = fpCreateDXGIFactory1(&IID_IDXGIFactory6, &dxgi_factory);\r\n                                                             ^\r\nthirdparty\\vulkan\\loader\\loader.c:6050:9: error: use of undeclared identifier 'dxgi_factory'\r\n        dxgi_factory->lpVtbl->Release(dxgi_factory);\r\n        ^\r\nthirdparty\\vulkan\\loader\\loader.c:6050:39: error: use of undeclared identifier 'dxgi_factory'\r\n        dxgi_factory->lpVtbl->Release(dxgi_factory);\r\n                                      ^\r\nthirdparty\\vulkan\\loader\\loader.c:7075:5: error: use of undeclared identifier 'IDXGIFactory6'\r\n    IDXGIFactory6* dxgi_factory = NULL;\r\n    ^\r\nthirdparty\\vulkan\\loader\\loader.c:7075:20: error: use of undeclared identifier 'dxgi_factory'\r\n    IDXGIFactory6* dxgi_factory = NULL;\r\n                   ^\r\nthirdparty\\vulkan\\loader\\loader.c:7076:42: error: use of undeclared identifier 'IID_IDXGIFactory6'\r\n    HRESULT hres = fpCreateDXGIFactory1(&IID_IDXGIFactory6, &dxgi_factory);\r\n                                         ^\r\nthirdparty\\vulkan\\loader\\loader.c:7076:62: error: use of undeclared identifier 'dxgi_factory'\r\n    HRESULT hres = fpCreateDXGIFactory1(&IID_IDXGIFactory6, &dxgi_factory);\r\n                                                             ^\r\nthirdparty\\vulkan\\loader\\loader.c:7093:68: error: called object type '<dependent type>' is not a function or function pointer\r\n            hres = dxgi_factory->lpVtbl->EnumAdapterByGpuPreference(dxgi_factory, i, DXGI_GPU_PREFERENCE_UNSPECIFIED, &IID_IDXGIAdapter1, &adapter);\r\n                                                                   ^\r\nthirdparty\\vulkan\\loader\\loader.c:7177:9: error: use of undeclared identifier 'dxgi_factory'\r\n        dxgi_factory->lpVtbl->Release(dxgi_factory);\r\n        ^\r\nthirdparty\\vulkan\\loader\\loader.c:7177:39: error: use of undeclared identifier 'dxgi_factory'\r\n        dxgi_factory->lpVtbl->Release(dxgi_factory);\r\n                                      ^\r\nthirdparty\\vulkan\\loader\\loader.c:7093:20: error: use of undeclared identifier 'dxgi_factory'\r\n            hres = dxgi_factory->lpVtbl->EnumAdapterByGpuPreference(dxgi_factory, i, DXGI_GPU_PREFERENCE_UNSPECIFIED, &IID_IDXGIAdapter1, &adapter);\r\n                   ^\r\nthirdparty\\vulkan\\loader\\loader.c:7093:69: error: use of undeclared identifier 'dxgi_factory'\r\n            hres = dxgi_factory->lpVtbl->EnumAdapterByGpuPreference(dxgi_factory, i, DXGI_GPU_PREFERENCE_UNSPECIFIED, &IID_IDXGIAdapter1, &adapter);\r\n                                                                    ^\r\nthirdparty\\vulkan\\loader\\loader.c:7093:86: error: use of undeclared identifier 'DXGI_GPU_PREFERENCE_UNSPECIFIED'\r\n            hres = dxgi_factory->lpVtbl->EnumAdapterByGpuPreference(dxgi_factory, i, DXGI_GPU_PREFERENCE_UNSPECIFIED, &IID_IDXGIAdapter1, &adapter);\r\n                                                                                     ^\r\n16 errors generated.\r\n"
=====
scons: *** [thirdparty\vulkan\loader\loader.windows.tools.64.o] Error 1
scons: building terminated because of errors.

[pouleyKetchoupp]

The error is due to requirements for recent dx11 headers for the api the vulkan loader is using.

On Windows, using a recent version of Mingw-w64 might help (version 8.0 from http://mingw-w64.org/doku.php). If in your case the headers come from the Windows SDK as it does for MSVC, installing a recent Windows SDK would work (https://developer.microsoft.com/en-us/windows/downloads/windows-10-sdk/).

For anybody interested, I was able to compile on Ubuntu 20.04, but because on the stable repo mingw-64 is still at version 7.0, I had to install it from a ppa.

First I had to remove the previous version of mingw entirely (otherwise I had discrepancies in headers):

sudo apt-get remove mingw-w64
sudo apt-get autoremove --purge

Then I've installed the new version from https://launchpad.net/~cybermax-dexter/+archive/ubuntu/mingw-w64-backport:

sudo add-apt-repository ppa:cybermax-dexter/mingw-w64-backport
sudo apt-get update
sudo apt-get install mingw-w64 gcc-mingw-w64