Rollup merge of #112858 - chriswailes:riscv64-android, r=Mark-Simulacrum

Update Android system definitions and add riscv-linux-android as tier 3 target

This PR includes the following:
* Corrected Android system definitions for some types
* Support for the riscv64-linux-android target

The authoritative types for the system definitions can be found here: https://cs.android.com/android/platform/superproject/+/master:bionic/libc/include/sys/stat.h

Fixes rust-lang/compiler-team#640

std/src/os/android/raw.rs

@@ -89,7 +89,7 @@ mod arch {
     }
 }
 
-#[cfg(target_arch = "aarch64")]
+#[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))]
 mod arch {
     use crate::os::raw::{c_int, c_long, c_uint, c_ulong};
     use crate::os::unix::raw::{gid_t, uid_t};