[BUILD] OpenVDB passes gcc style flags to MSVC

[LazyDodo]

Environment

Operating System: Win10
Version / Commit SHA: VDB 10.0
CMake Version: 3.24.2
Compiler: msvc 2019

Describe the problem

When setting -DOPENVDB_SIMD=SSE42 OpenVDB's cmake passes the GCC style flags directly to MSVC over in CMakeLists.txt@386

To Reproduce

Steps to reproduce the behavior:

1. Build with -DOPENVDB_SIMD=SSE42 or -DOPENVDB_SIMD=AVX with MSVC
2. cl : Command line warning D9002: ignoring unknown option '-msse4.2' [c:\db\build\S\VS1564D\openvdb.vcxproj]

Additional context

MSVC doesn't have a flag for SSE42, but if you call the sse42 intrinsics like openvdb does the right opcodes will still be generated, AVX can be enabled with /arch:AVX source

[Idclip]

Hey @LazyDodo thanks for reporting this, this has now been fixed #1645 (though as an aside, the way we handle hardware instrumentation in general isn't correct and we're planning of restructuring this in the future)