* This change was authored by bclayton@, with some modifications.
* Replaces Win32 fiber implementation with marl tasks, making coroutines
  work on all marl-supported platforms.

Bug: b/145754674
Change-Id: Ic3de82afc69549e1d56688c6faf8077a6f446ee0
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/41788
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Antonio Maiorano <amaiorano@google.com>