Summary:
These warnings were present when building llvm-libc in release mode.
```
workspace/llvm-project/libc/utils/benchmarks/LibcMemoryBenchmarkTest.cpp:50:34: warning: 'None' is deprecated: Use Align() or Align(1) instead [-Wdeprecated-declarations]
Conf.AddressAlignment = Align::None();
workspace/llvm-project/libc/utils/testutils/FDReaderUnix.cpp:19:7: warning: unused variable 'err' [-Wunused-variable]
int err = ::pipe(pipefd);
```
For test-utils it seems in general we should use `report_fatal_error` instead of asserts as these are turned off when building in release mode.
https://llvm.org/docs/CodingStandards.html#assert-liberally
Reviewers: abrachet, sivachandra
Reviewed By: abrachet, sivachandra
Subscribers: tschuett, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D79469
Summary: Adds `write` for Linux and FDReader utility which should be useful for some stdio tests as well.
Reviewers: sivachandra, PaulkaToast
Reviewed By: sivachandra
Subscribers: mgorny, tschuett, libc-commits
Differential Revision: https://reviews.llvm.org/D78184