Rollup merge of rust-lang#22758 - ejjeong:aarch64-linux-android, r=alexcrichton

 This commit has already been merged in rust-lang#21774,
but i think it has been accidently overriden by rust-lang#22584 and rust-lang#22480.
r? @alexcrichton

Author: Manishearth

src/libstd/sys/unix/process.rs

@@ -69,7 +69,6 @@ impl Process {
               K: BytesContainer + Eq + Hash, V: BytesContainer
     {
         use libc::funcs::posix88::unistd::{fork, dup2, close, chdir, execvp};
-        use libc::funcs::bsd44::getdtablesize;
 
         mod rustrt {
             extern {
@@ -82,6 +81,15 @@ impl Process {
             assert_eq!(ret, 0);
         }
 
+        #[cfg(all(target_os = "android", target_arch = "aarch64"))]
+        unsafe fn getdtablesize() -> c_int {
+            libc::sysconf(libc::consts::os::sysconf::_SC_OPEN_MAX) as c_int
+        }
+        #[cfg(not(all(target_os = "android", target_arch = "aarch64")))]
+        unsafe fn getdtablesize() -> c_int {
+            libc::funcs::bsd44::getdtablesize()
+        }
+
         let dirp = cfg.cwd().map(|c| c.as_ptr()).unwrap_or(ptr::null());
 
         // temporary until unboxed closures land

src/libstd/sys/unix/process2.rs

@@ -141,7 +141,6 @@ impl Process {
                  -> io::Result<Process>
     {
         use libc::funcs::posix88::unistd::{fork, dup2, close, chdir, execvp};
-        use libc::funcs::bsd44::getdtablesize;
 
         mod rustrt {
             extern {
@@ -154,6 +153,16 @@ impl Process {
             assert_eq!(ret, 0);
         }
 
+        #[cfg(all(target_os = "android", target_arch = "aarch64"))]
+        unsafe fn getdtablesize() -> c_int {
+            libc::sysconf(libc::consts::os::sysconf::_SC_OPEN_MAX) as c_int
+        }
+
+        #[cfg(not(all(target_os = "android", target_arch = "aarch64")))]
+        unsafe fn getdtablesize() -> c_int {
+            libc::funcs::bsd44::getdtablesize()
+        }
+
         let dirp = cfg.cwd.as_ref().map(|c| c.as_ptr()).unwrap_or(ptr::null());
 
         with_envp(cfg.env.as_ref(), |envp: *const c_void| {