编译android平台库时，编译出错

[stopandjoin]

按照文档指引，已安装所有环境。
Ubuntu20 环境下编译， 出错：
cargo ndk -t arm64-v8a -p 21 -- build --features ffi --release
Building arm64-v8a (aarch64-linux-android)
Compiling proc-macro2 v1.0.79
Compiling unicode-ident v1.0.12
Compiling autocfg v1.1.0
Compiling libc v0.2.153
Compiling cc v1.0.90
Compiling serde v1.0.197
error[E0463]: can't find crate for core
|
= note: the aarch64-linux-android target may not be installed
= help: consider downloading the target with rustup target add aarch64-linux-android

error[E0463]: can't find crate for compiler_builtins

error[E0432]: unresolved import ffi::c_void
--> /home/lxc/.cargo/registry/src/index.crates.io-6f17d22bba15001f/libc-0.2.153/src/unix/mod.rs:1590:17
|
1590 | pub use ::ffi::c_void;
| ^^^^^^^^^^^^^

Some errors have detailed explanations: E0432, E0463.
For more information about an error, try rustc --explain E0432.
error: could not compile libc (lib) due to 3 previous errors
warning: build failed, waiting for other jobs to finish...
note: If the build failed due to a missing target, you can run this command:
note:
note: rustup target install aarch64-linux-android

[glime-ai[bot]]

Based on the error messages you've encountered, it seems like the root cause is that the Rust compiler cannot find the standard library for the aarch64-linux-android target. This typically happens when the target platform is not installed in your Rust toolchain. The error message even suggests a solution: to download the target using rustup target add aarch64-linux-android.

To resolve this issue, you should follow these steps:

1. Ensure that you have the Rust toolchain installed. If not, you can install it from https://www.rust-lang.org/tools/install.
2. Add the aarch64-linux-android target to your Rust toolchain by running the command suggested in the error message:

   rustup target add aarch64-linux-android
   

3. Once the target is added, try running your build command again:

   cargo ndk -t arm64-v8a -p 21 -- build --features ffi --release
   

This should resolve the errors related to not finding the core and compiler_builtins crates, as well as the unresolved import of ffi::c_void.

Additionally, ensure that you have the Android NDK installed and the ANDROID_NDK_HOME environment variable set correctly, as mentioned in the documentation. This is crucial for building projects targeting Android.

If you encounter further issues or the problem persists, consider checking the documentation for any additional prerequisites or steps that might have been missed, and ensure that all dependencies and tools are up to date.

[stopandjoin]

以上工具都安装过了，问题没有解决。

[stopandjoin]

求助一下 @iyangsj

[iyangsj]

注意使用rust官方方式来安装rust工具链，不要直接使用ubuntu的包管理工具来安装

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup update

[iyangsj]

类似问题：rust-lang/rustup#3426