Some applications use this for debug logging. Better to return zero than
uninitialized data.

This adds a build-time dependency on openal, and a run-time dependency
on openal-soft's ALC_SOFT_loopback extension.

Required for PDF printing in OrCAD 16.6.

d2d1: Avoid leaking "object" on an error path in d2d_factory_CreateWicBitmapRenderTarget() (Coverity).

Mostly just for consistency with other D3D code.

d3d11_1.h includes d3d11.h, which includes d3d10_1.h.

d3d11.h includes d3d10_1.h, which includes d3d10.h.