Repro (Windows)

• OS: Windows 10/11 (AMD64)
• CMake: (paste output of: cmake --version)
• Generator: (Ninja or Visual Studio 17 2022)

Steps:

1. Remove build dir
2. cmake -S . -B build -G

Actual

• Configure fails because 'uname' is not available on Windows
• Arch detection misses AMD64 in x86_64 checks
• 'polluted env flags' check can fail on Windows where MSVC sets default flags

Expected

• CMake configure succeeds on Windows with default MSVC environment.