rollup merge of #21414: ejjeong/aarch64-linux-android

Initial support for aarch64-linux-android (#18920)
- Add new configuration files
- Modify some options to compile & link succesfully.
  (PIE, disable tls on jemalloc, modify some external function linkage, ..)
- To build, refer to https://github.com/rust-lang/rust/wiki/Doc-building-for-android.
   (tested with platform=21 and toolchain=aarch64-linux-android-4.9)

src/libstd/sys/unix/backtrace.rs

@@ -418,7 +418,7 @@ mod uw {
                                  trace_argument: *mut libc::c_void)
                     -> _Unwind_Reason_Code;
 
-        #[cfg(all(not(target_os = "android"),
+        #[cfg(all(not(all(target_os = "android", target_arch = "arm")),
                   not(all(target_os = "linux", target_arch = "arm"))))]
         pub fn _Unwind_GetIP(ctx: *mut _Unwind_Context) -> libc::uintptr_t;
 
@@ -431,7 +431,7 @@ mod uw {
     // On android, the function _Unwind_GetIP is a macro, and this is the
     // expansion of the macro. This is all copy/pasted directly from the
     // header file with the definition of _Unwind_GetIP.
-    #[cfg(any(target_os = "android",
+    #[cfg(any(all(target_os = "android", target_arch = "arm"),
               all(target_os = "linux", target_arch = "arm")))]
     pub unsafe fn _Unwind_GetIP(ctx: *mut _Unwind_Context) -> libc::uintptr_t {
         #[repr(C)]