Configs still to add: android, darwin, fuchsia, windows

Bug: b/152339534
Change-Id: I721b7a69a0a1e84f09158329557264bf2af9c5d6
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43009Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>