all default latest experimental legacy oldest sys bindist linux macos freebsd windows gcc clang msvc static ndebug optimized relocatable gcc-4.9+ gcc-5+:gcc-4.9+ gcc-6+:gcc-5+ gcc-7+:gcc-6+ gcc-8+:gcc-7+ gcc-9+:gcc-8+ gcc-10+:gcc-9+ gcc-11+:gcc-10+ gcc-12+:gcc-11+ gcc-13+:gcc-12+ gcc-14+:gcc-13+ gcc-15+:gcc-14+ gcc-16+:gcc-15+ clang-3.7+ clang-3.8+:clang-3.7+ clang-3.9+:clang-3.8+ clang-4+:clang-3.9+ clang-5+:clang-4+ clang-6+:clang-5+ clang-7+:clang-6+ clang-8+:clang-7+ clang-9+:clang-8+ clang-10+:clang-9+ clang-11+:clang-10+ clang-12+:clang-11+ clang-13+:clang-12+ clang-14+:clang-13+ clang-15+:clang-14+ clang-16+:clang-15+ clang-17+:clang-16+ clang-18+:clang-17+ clang-19+:clang-18+ clang-20+:clang-19+ clang-21+:clang-20+ clang-22+:clang-21+ msvc-14+ msvc-14.3+:msvc-14+ msvc-15+:msvc-14.3+ msvc-15.9+:msvc-15+ msvc-16+:msvc-15.9+ msvc-16.11+:msvc-16+ msvc-17+:msvc-16.11+ msvc-18+:msvc-17+ host build2