Output intermediate build files to project independent directories.

Output intermediate build files to project independent directories.

This prevents clashes between intermediates. Also update the D3D8
project to not depend on debug macro implementations in the
SwiftShader layer.

Bug b/29024574

Change-Id: I206b750bf752e3b47867f35379a82f32549a7843
Reviewed-on: https://swiftshader-review.googlesource.com/c/21348
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>