Cannot compile with LLVM/Ninja on Windows due to /utf-8 #4158
Description
Fmt has started adding /utf-8 flags when installed through vcpkg on Windows even though it's not supported by Clang.
https://github.com/aminya/cpp_vcpkg_project/actions/runs/10810623863/job/29988266523?pr=55#step:6:213
Here's a full reproduction:
https://github.com/aminya/cpp_vcpkg_project/tree/a53c2ce04dd16a26a60a3c1d85d2df212977319a
Here are some generated code in build/vcpkg_installed/x64-windows/share/fmt/fmt-targets.cmake
# Create imported target fmt::fmt
add_library(fmt::fmt SHARED IMPORTED)
set_target_properties(fmt::fmt PROPERTIES
INTERFACE_COMPILE_DEFINITIONS "FMT_SHARED"
INTERFACE_COMPILE_FEATURES "cxx_std_11"
INTERFACE_COMPILE_OPTIONS "\$<\$<COMPILE_LANGUAGE:CXX>:/utf-8>"
INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include"
)
# Create imported target fmt::fmt-header-only
add_library(fmt::fmt-header-only INTERFACE IMPORTED)
set_target_properties(fmt::fmt-header-only PROPERTIES
INTERFACE_COMPILE_DEFINITIONS "FMT_HEADER_ONLY=1"
INTERFACE_COMPILE_FEATURES "cxx_std_11"
INTERFACE_COMPILE_OPTIONS "\$<\$<COMPILE_LANGUAGE:CXX>:/utf-8>"
INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include"
)This should be conditional. Although vcpkg might use its own toolchain, it doesn't mean the cmake file is going to be used with MSVC. This includes clang-tidy usage (different at build time than configuration time).