Rollup merge of rust-lang#90834 - cuviper:android-gnu, r=petrochenkov

Android is not GNU

For a long time, the Android targets had `target_env=""`, but this changed to `"gnu"` in Rust 1.49.0. I tracked this down to rust-lang#77729 which started setting `"gnu"` in the `linux_base` target options, and this was inherited by `android_base`. Then rust-lang#78929 split the env into `linux_gnu_base`, but `android_base` was also changed to follow that. Android was not specifically mentioned in either pull request, so I believe this was an accident. Moving it back to `linux_base` will use an empty `env` again.

r? ``@Mark-Simulacrum``
cc ``@petrochenkov``

compiler/rustc_target/src/spec/android_base.rs

@@ -1,7 +1,7 @@
 use crate::spec::{LinkerFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
-    let mut base = super::linux_gnu_base::opts();
+    let mut base = super::linux_base::opts();
     base.os = "android".to_string();
     // Many of the symbols defined in compiler-rt are also defined in libgcc.
     // Android's linker doesn't like that by default.