Auto merge of #2259 - devnexen:android_arc4api, r=JohnTitor

android introduce arc4 api

Author: bors

libc-test/semver/android.txt

@@ -2572,6 +2572,9 @@ addrinfo
 af_alg_iv
 alarm
 android_set_abort_message
+arc4random
+arc4random_buf
+arc4random_uniform
 arphdr
 arpreq
 arpreq_old

src/unix/linux_like/android/mod.rs

@@ -2875,6 +2875,10 @@ extern "C" {
         >,
         data: *mut ::c_void,
     ) -> ::c_int;
+
+    pub fn arc4random() -> u32;
+    pub fn arc4random_uniform(__upper_bound: u32) -> u32;
+    pub fn arc4random_buf(__buf: *mut ::c_void, __n: ::size_t);
 }
 
 cfg_if! {