[libigl] Mark supports UWP.

[BillyONeal]

This seemed to work in my testing in #47156 (comment)

Related: #47815

[BillyONeal]

(Note build failure is intentional right now because I intentionally did not update version DB because I want to see what results come back)

[BillyONeal]

@dg0yt Do you remember why you added that "supports"?

[dg0yt]

Looking up the PR, #47815:

But in the end, I restored the header-only configuration, now subject to a triplet variable.

The header-only installation will never fail.
The test port cascades due to glfw.

Set LIBIGL_USE_STATIC_LIBRARY to 1 in the triplet to actually compile code for UWP.

[BillyONeal]

Set LIBIGL_USE_STATIC_LIBRARY to 1 in the triplet to actually compile code for UWP.

Ah, there's the errors:

C:\Dev\vcpkg\buildtrees\libigl\src\v2.6.0-4736a7a7d0.clean\include\igl\file_dialog_save.cpp(56): error C2065: 'OPENFILENAME': undeclared identifier
C:\Dev\vcpkg\buildtrees\libigl\src\v2.6.0-4736a7a7d0.clean\include\igl\file_dialog_save.cpp(56): error C2146: syntax error: missing ';' before identifier 'ofn'
C:\Dev\vcpkg\buildtrees\libigl\src\v2.6.0-4736a7a7d0.clean\include\igl\file_dialog_save.cpp(56): error C2065: 'ofn': undeclared identifier
C:\Dev\vcpkg\buildtrees\libigl\src\v2.6.0-4736a7a7d0.clean\include\igl\file_dialog_save.cpp(60): error C2065: 'ofn': undeclared identifier
C:\Dev\vcpkg\buildtrees\libigl\src\v2.6.0-4736a7a7d0.clean\include\igl\file_dialog_save.cpp(61): error C2065: 'ofn': undeclared identifier
C:\Dev\vcpkg\buildtrees\libigl\src\v2.6.0-4736a7a7d0.clean\include\igl\file_dialog_save.cpp(61): error C2065: 'ofn': undeclared identifier

Makes sense that the classic dialogs aren't a thing in UWP mode