Fixes Visual Studio build issues.

Bug swiftshader:115

Change-Id: Ibd09f4de84a115ed1b264b36985d2d4f31fb3a97
Reviewed-on: https://swiftshader-review.googlesource.com/20269Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>