Capture Android under the 'linux' cfg

Rust differentiates between Linux and Android at the cfg level.
Conceptually, when we say we support Linux that includes Android as
well (though we can't run tests on Android at the moment, due to
libbpf-sys not being able to compile for it).
To enshrine this constraint into our code base, adjust our 'linux' cfg
alias to include the 'android' target_os as well.

Signed-off-by: Daniel Müller <deso@posteo.net>

build.rs

@@ -2,6 +2,6 @@ use cfg_aliases::cfg_aliases;
 
 fn main() {
     cfg_aliases! {
-        linux: { target_os = "linux" },
+        linux: { any(target_os = "linux", target_os = "android") },
     }
 }

dev/Cargo.toml

@@ -39,5 +39,5 @@ xz2 = {version = "0.1.7", optional = true}
 zip = {version = "2.0.0", optional = true, default-features = false}
 zstd = {version = "0.13.1", default-features = false, optional = true}
 
-[target.'cfg(target_os = "linux")'.build-dependencies]
+[target.'cfg(any(target_os = "linux", target_os = "android"))'.build-dependencies]
 libbpf-sys = {version = "1.4.1", default-features = false, optional = true}

dev/build.rs

@@ -32,7 +32,7 @@ fn data_dir() -> PathBuf {
 }
 
 /// Retrieve the system's page size.
-#[cfg(target_os = "linux")]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 fn page_size() -> Result<usize> {
     // SAFETY: `sysconf` is always safe to call.
     let rc = unsafe { libc::sysconf(libc::_SC_PAGE_SIZE) };
@@ -45,7 +45,7 @@ fn page_size() -> Result<usize> {
     Ok(usize::try_from(rc).unwrap())
 }
 
-#[cfg(not(target_os = "linux"))]
+#[cfg(not(any(target_os = "linux", target_os = "android")))]
 fn page_size() -> Result<usize> {
     unimplemented!()
 }