Simplify architecture detection for 64/32 bits on Windows and fix VPX build where libraries couldn't be found in MS2.
Cherry-picks: !2698 (merged)
BC/public/external/decaf!17 (merged)
MR: mediastreamer2!612 (merged)
Simplify architecture detection for 64/32 bits on Windows and fix VPX build where libraries couldn't be found in MS2.
Cherry-picks: !2698 (merged)
BC/public/external/decaf!17 (merged)
MR: mediastreamer2!612 (merged)