[libc] [llvm] [libc] add remaining epoll functions, pipe (PR #84587)

[Nick Desaulniers via llvm-commits]

================
@@ -0,0 +1,22 @@
+//===-- Unittests for epoll_create ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#include "src/errno/libc_errno.h"
+#include "src/sys/epoll/epoll_create.h"
+#include "src/unistd/close.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+
+TEST(LlvmLibcEpollCreateTest, Basic) {
+  int fd = LIBC_NAMESPACE::epoll_create(1);
----------------
nickdesaulniers wrote:

https://android.googlesource.com/platform/bionic/+/refs/heads/main/tests/sys_epoll_test.cpp has a test that input `0` fails. Consider adding a test for that.

https://github.com/llvm/llvm-project/pull/84587