gltrace: Fix emission of fake viewport/scissor on MacOSX.
egltrace: Fix eglGetConfigs/eglChooseConfig prototypes.

`configs` is an output parameter.
gltrace: Support GL_NV_blend_equation_advanced.
gltrace: Trace GL_NV_vdpau_interop.

Traces won't be replayable, but this will at least prevent the

  apitrace: warning: unknown function "glVDPAU*"

warnings.