[libc-commits] [libc] [libc] Add realpath to linux entrypoints (PR #212925)

[Jackson Stogel via libc-commits]

jtstogel wrote:

*sigh* it seems like `libc-riscv32-qemu-yocto-fullbuild-dbg` uses a symlink or something for `/tmp` that points to `/var/volatile/tmp`, while realpath tests assume that `/tmp` is a real dircetory.

```
[ RUN      ] LlvmLibcRealpathTest.DotTraversalIsNop
/home/libcrv32buildbot/bbroot/libc-riscv32-qemu-yocto-fullbuild-dbg/llvm-project/libc/test/src/stdlib/realpath_test.cpp:376: FAILURE
      Expected: realpath_buffered(test_dir.absolute_path("a/b/./"))
      Which is: /var/volatile/tmp/LlvmLibcRealpathTest.DotTraversalIsNop.26392.spwgu9wizj1367ld/a/b
To be equal to: test_dir.absolute_path("a/b").c_str()
      Which is: /tmp/LlvmLibcRealpathTest.DotTraversalIsNop.26392.spwgu9wizj1367ld/a/b
```

https://github.com/llvm/llvm-project/pull/212925