[libc][POSIX] generate sys/wait.h for aarch64

[nickdesaulniers]

In order to make out unit tests hermetic for cross compilation, we need to implement waitpid from sys/wait.h for use in libc/test/UnitTest/ExecuteFunctionUnix.cpp.

[llvmbot]

@llvm/issue-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

In order to make out unit tests hermetic for cross compilation, we need to implement `waitpid` from sys/wait.h for use in libc/test/UnitTest/ExecuteFunctionUnix.cpp.

[nickdesaulniers]

uh...what? We already have a waitpid (995105d). And it's being declared in our generated sys/wait.h...

It seems that our generated build_dir/libc/include/sys/wait.h is...empty...

libc.src.sys.wait.waitpid is a defined entrypoint in libc/config/linux/aarch64/entrypoints.txt

Ah! But libc.include.sys_wait is not in libc/config/linux/aarch64/headers.txt. Should be trivial to add it, if someone is looking for a softball.

[llvmbot]

Hi!

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[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Nick Desaulniers (nickdesaulniers)

In order to make out unit tests hermetic for cross compilation, we need to implement `waitpid` from sys/wait.h for use in libc/test/UnitTest/ExecuteFunctionUnix.cpp.