[libcxx-commits] [libcxx] [libc++] Build the library with C++26 (PR #181021)

[Louis Dionne via libcxx-commits]

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@@ -504,11 +504,9 @@ remove_flags(-Wno-pedantic -pedantic-errors -pedantic)
 # Required flags ==============================================================
 function(cxx_add_basic_build_flags target)
 
-  # Use C++23 for all targets.
-  set_target_properties(${target} PROPERTIES
-    CXX_STANDARD 23
-    CXX_STANDARD_REQUIRED OFF # TODO: Make this REQUIRED once we don't need to accommodate the LLVM documentation builders using an ancient CMake
-    CXX_EXTENSIONS NO)
+  # Use C++26 for all targets. Note that we don't use CXX_STANDARD or cxx_std_foo
+  # since that requires a newer CMake than is available.
+  target_compile_options(${target} PRIVATE $<IF:$<CXX_COMPILER_ID:MSVC>,/std:c++26,-std=c++26>)
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ldionne wrote:

The goal here was indeed to support clang-cl, which we are using on some of the CI bots. I'll switch to `/std:c++latest`.

https://github.com/llvm/llvm-project/pull/181021