llvm-project

648981f9 - [libc] Build with -Wdeprecated, fix some warnings (#125373)

[libc] Build with -Wdeprecated, fix some warnings (#125373) While GCC's -Wdeprecated is on by default and doesn't do much, Clang's -Wdeprecated enables many more things. More apply in C++20, so switch a test file that tickled one to using that. In future, C++20 should probably be made the baseline for compiling all the libc code.