CMake: add C4471 warning as error for MSVC: enum forward declare must have underlying type
CMake: add C4471 warning as error for MSVC: enum forward declare must have underlying type

Bug: b/131224705
Change-Id: I7f971cd72ab623ba3798231b8b2a1b77e7744f78
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31369
Presubmit-Ready: Antonio Maiorano <86d87a6550afb6b07035c9743fa181900589f7e0@google.com>
Kokoro-Presubmit: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Tested-by: Antonio Maiorano <86d87a6550afb6b07035c9743fa181900589f7e0@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader