[libc][c11] add support for stdio.h's rename()

[nickdesaulniers]

See also 7.23.4.2 The rename function in n3096

libc++ needs this for LIBCXX_ENABLE_FILESYSTEM support.

[llvmbot]

@llvm/issue-subscribers-libc

Author: Nick Desaulniers (nickdesaulniers)

See also `7.23.4.2 The rename function` in n3096

[llvmbot]

@llvm/issue-subscribers-c11

Author: Nick Desaulniers (nickdesaulniers)

See also `7.23.4.2 The rename function` in n3096

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. In the comments of the issue, request for it to be assigned to you.
2. Fix the issue locally.
3. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
4. Create a Git commit.
5. Run git clang-format HEAD~1 to format your changes.
6. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

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

Author: Nick Desaulniers (nickdesaulniers)

See also `7.23.4.2 The rename function` in n3096

libc++ needs this for LIBCXX_ENABLE_FILESYSTEM support.

[aniplcc]

Would the implementation be somewhat as in stdio.h's remove() using syscalls? I'll create a PR.

[AtharvKshirsagar]

Hi I am Atharv Kshirsagar from IIT Bombay.I would like to request you to grant me access to the issue.Thanks

[nickdesaulniers]

Hi @AtharvKshirsagar , @aniplcc already is working on this (is assigned, and their PR is linked above). Thanks for your interest, but there may be another bug that's a better place to start.