[libcxx-commits] [libcxx] [libc++][z/OS] Move z/OS to new locale API and resolve all name collisions (PR #165428)

[Louis Dionne via libcxx-commits]

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ldionne wrote:

Since we `#undef __islower` in `__undef_macros`, I don't understand why we can't just define `__islower` here and have to do a dance around `islower_l`.

We shouldn't define non-reserved symbols like `islower_l` in the dylib, that's the responsibility of whichever library owns that symbol.

https://github.com/llvm/llvm-project/pull/165428