feat(ohos): fix some compilation errors and add some features

[richerfu]

What does this PR do

This PR fix some compilation errors for OpenHarmony. I'll try to explain the following changes.

1. The basic c library for OpenHarmony is forked from musl(1.25), so it's reasonable for us to follow the musl condition compilation.
2. According to the document, some symbols don't export. So aio and mqueue should be hidden for OpenHarmony.
3. OpenHarmony support more enum for memfd, the following code is the content of memfd.h:

 /****************************************************************************
 ****************************************************************************
 ***
 ***   This header was automatically generated from a Linux kernel header
 ***   of the same name, to make information necessary for userspace to
 ***   call into the kernel available to libc.  It contains only constants,
 ***   structures, and macros generated from the original header, and thus,
 ***   contains no copyrightable information.
 ***
 ***   To edit the content of this header, modify the corresponding
 ***   source file (e.g. under external/kernel-headers/original/) then
 ***   run bionic/libc/kernel/tools/update_all.py
 ***
 ***   Any manual change here will be lost the next time this script will
 ***   be run. You've been warned!
 ***
 ****************************************************************************
 ****************************************************************************/
#ifndef _UAPI_LINUX_MEMFD_H
#define _UAPI_LINUX_MEMFD_H
#include <asm-generic/hugetlb_encode.h>
#define MFD_CLOEXEC 0x0001U
#define MFD_ALLOW_SEALING 0x0002U
#define MFD_HUGETLB 0x0004U
#define MFD_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
#define MFD_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
#define MFD_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB
#define MFD_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
#define MFD_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
#define MFD_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
#define MFD_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
#define MFD_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB
#define MFD_HUGE_32MB HUGETLB_FLAG_ENCODE_32MB
#define MFD_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
#define MFD_HUGE_512MB HUGETLB_FLAG_ENCODE_512MB
#define MFD_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
#define MFD_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
#define MFD_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
#endif

4. NDK include the epoll.h and eventfd.h file, so i think epoll and eventfd can be used for OHOS

This PR don't change any nix's API, so i think i don't need to add a changelog right? Hope you can give me some suggestion thanks.

Checklist:

• I have read CONTRIBUTING.md
• I have written necessary tests and rustdoc comments
• A change log has been added if this PR modifies nix

[richerfu]

And i use it to implement a simple traceroute, everything seems to be in order.

[SteveLauC]

Sorry for the late review, thanks for the ping

Appreciate the explanation, it helps code review a lot!

[SteveLauC]

This PR don't change any nix's API, so i think i don't need to add a changelog right? Hope you can give me some suggestion thanks.

APIs are not changed, but if you want, you can leave a changelog like this:

file name: 2587.fixed.md

fixes the build on OpenHarmony

[richerfu]

This PR don't change any nix's API, so i think i don't need to add a changelog right? Hope you can give me some suggestion thanks.

APIs are not changed, but if you want, you can leave a changelog like this:

file name: 2587.fixed.md
fixes the build on OpenHarmony

Thanks for your review, i've already finished all of comments. Please see it again, thanks

[SteveLauC]

Regarding the changes in tests, does cargo test work under ohos?

[SteveLauC]

I am thinking about adding CI for:

1. aarch64-unknown-linux-ohos
2. x86_64-unknown-linux-ohos

Are you willing to do this after merging this PR? It is simple:

1. Add these 2 targets in the CI file:

   nix/.github/workflows/ci.yml

   Line 238 in 299feba

   - target: x86_64-unknown-netbsd

2. Add them to the supported tier2 targets (The list needs to be ordered):

   nix/README.md

   Lines 82 to 92 in 299feba

   	<li>aarch64-apple-ios</li>
   	<li>aarch64-linux-android</li>
   	<li>arm-linux-androideabi</li>
   	<li>arm-unknown-linux-musleabi</li>
   	<li>armv7-linux-androideabi</li>
   	<li>i686-linux-android</li>
   	<li>loongarch64-unknown-linux-gnu</li>
   	<li>s390x-unknown-linux-gnu</li>
   	<li>x86_64-linux-android</li>
   	<li>x86_64-unknown-illumos</li>
   	<li>x86_64-unknown-netbsd</li>

[richerfu]

Regarding the changes in tests, does cargo test work under ohos?

Unfortunately we can't run cargo test within harmony device, there isn't available emulator to run it.

[richerfu]

I am thinking about adding CI for:

1. aarch64-unknown-linux-ohos
2. x86_64-unknown-linux-ohos

Are you willing to do this after merging this PR? It is simple:

1. Add these 2 targets in the CI file:

   nix/.github/workflows/ci.yml

   Line 238 in 299feba

   - target: x86_64-unknown-netbsd

2. Add them to the supported tier2 targets (The list needs to be ordered):

   nix/README.md

   Lines 82 to 92 in 299feba

   	<li>aarch64-apple-ios</li>
   	<li>aarch64-linux-android</li>
   	<li>arm-linux-androideabi</li>
   	<li>arm-unknown-linux-musleabi</li>
   	<li>armv7-linux-androideabi</li>
   	<li>i686-linux-android</li>
   	<li>loongarch64-unknown-linux-gnu</li>
   	<li>s390x-unknown-linux-gnu</li>
   	<li>x86_64-linux-android</li>
   	<li>x86_64-unknown-illumos</li>
   	<li>x86_64-unknown-netbsd</li>

Sure, i'll add them later

[SteveLauC]

Regarding the changes in tests, does cargo test work under ohos?

Unfortunately we can't run cargo test within harmony device, there isn't available emulator to run it.

Get it

[SteveLauC]

Thanks!