Build fixes for OSL on Windows #3980

Job	Run time
macos-13 C++17 py3.11 MacOS-13 llvm17	26m 34s
Ubuntu Debug gcc7/C++17 llvm11 py3.8 oiio2.5 exr3.1 sse4	24m 39s
macos-14 C++17 py3.11 MacOS-14-ARM llvm17	11m 19s
VFX2021 gcc9/C++17 llvm11 py3.7 oiio2.5 sse4 batch-b8avx2	15m 27s
Ubuntu gcc10/C++17 llvm11 oiio-2.5 avx2	8m 7s
VFX2023 gcc11/C++17 llvm15 py3.10 oiio-rel avx2	18m 24s
VFX2022 gcc9/C++17 llvm13 py3.9 exr3.1 oiio-rel avx2	16m 51s
Ubuntu latest releases gcc11/C++17 llvm17 oiio-3.0 exr3.2 py3.12 avx2 batch-b16avx512	29m 12s
VFX2023 GPU Cuda11 gcc11/C++17 llvm15 py3.10 OIIO-main avx2	6m 13s
VFX2022 clang12/C++17 llvm12 oiio-main py3.9 avx2 batch-avx512	17m 23s
Ubuntu bleeding edge gcc12/C++17 llvm17 oiio/ocio/exr/pybind-main py3.12 avx2 batch-b16avx512	14m 26s
VFX2022 gcc9/C++17 llvm11 py3.9 exr3.1 oiio3.0 sse2 batch-b4sse2	15m 15s
VFX2024 gcc11/C++17 llvm17 py3.11 boost1.82 oiio-rel avx2	21m 44s
Ubuntu clang14/C++17 llvm14 py3.8 avx2 batch-b16avx512	14m 6s
VFX2021 oldest everything gcc9/C++17 llvm9 py3.7 oiio2.5 no-simd	9m 42s
VFX2024 sanitizers	31m 12s
Ubuntu clang-format	4m 37s
VFX2023 abi check	10m 36s
VFX2023 icc/C++17 llvm14 py3.9 oiio-main avx2	21m 7s
VFX2023 icx/C++17 llvm14 py3.10 oiio-3.0 avx2	20m 27s
	5h 37m 21s

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