Rollup merge of #143747 - Gelbpunkt:aarch64-musl-maintainer, r=jieyouxu

Add target maintainer information for aarch64-unknown-linux-musl

Mentioning `@famfo` so that they can review the documentation. We're both very invested in this target; I originally promoted it to tier 2 with host tools in #76420 back in 2020.

Author: matthiaskrgr

src/doc/rustc/src/SUMMARY.md

@@ -46,6 +46,7 @@
     - [\*-apple-watchos](platform-support/apple-watchos.md)
     - [\*-apple-visionos](platform-support/apple-visionos.md)
     - [aarch64-nintendo-switch-freestanding](platform-support/aarch64-nintendo-switch-freestanding.md)
+    - [aarch64-unknown-linux-musl](platform-support/aarch64-unknown-linux-musl.md)
     - [amdgcn-amd-amdhsa](platform-support/amdgcn-amd-amdhsa.md)
     - [armeb-unknown-linux-gnueabi](platform-support/armeb-unknown-linux-gnueabi.md)
     - [arm-none-eabi](platform-support/arm-none-eabi.md)

src/doc/rustc/src/platform-support.md

@@ -90,7 +90,7 @@ target | notes
 -------|-------
 [`aarch64-pc-windows-gnullvm`](platform-support/windows-gnullvm.md) | ARM64 MinGW (Windows 10+), LLVM ABI
 [`aarch64-pc-windows-msvc`](platform-support/windows-msvc.md) | ARM64 Windows MSVC
-`aarch64-unknown-linux-musl` | ARM64 Linux with musl 1.2.3
+[`aarch64-unknown-linux-musl`](platform-support/aarch64-unknown-linux-musl.md) | ARM64 Linux with musl 1.2.3
 [`aarch64-unknown-linux-ohos`](platform-support/openharmony.md) | ARM64 OpenHarmony
 `arm-unknown-linux-gnueabi` | Armv6 Linux (kernel 3.2+, glibc 2.17)
 `arm-unknown-linux-gnueabihf` | Armv6 Linux, hardfloat (kernel 3.2+, glibc 2.17)

src/doc/rustc/src/platform-support/aarch64-unknown-linux-musl.md

@@ -0,0 +1,49 @@
+# aarch64-unknown-linux-musl
+
+**Tier: 2**
+
+Target for 64-bit little endian ARMv8-A Linux programs using musl libc.
+
+## Target maintainers
+
+[@Gelbpunkt](https://github.com/Gelbpunkt)
+[@famfo](https://github.com/famfo)
+
+## Requirements
+
+Building the target itself requires a 64-bit little endian ARMv8-A compiler
+that is supported by `cc-rs`.
+
+## Building the target
+
+The target can be built by enabling it for a `rustc` build.
+
+```toml
+[build]
+target = ["aarch64-unknown-linux-musl"]
+```
+
+Make sure your C compiler is included in `$PATH`, then add it to the
+`bootstrap.toml`:
+
+```toml
+[target.aarch64-unknown-linux-musl]
+cc = "aarch64-linux-musl-gcc"
+cxx = "aarch64-linux-musl-g++"
+ar = "aarch64-linux-musl-ar"
+linker = "aarch64-linux-musl-gcc"
+```
+
+## Building Rust programs
+
+This target is distributed through `rustup`, and otherwise requires no
+special configuration.
+
+## Cross-compilation
+
+This target can be cross-compiled from any host.
+
+## Testing
+
+This target can be tested as normal with `x.py` on a 64-bit little endian
+ARMv8-A host or via QEMU emulation.