Merge branch 'fix_aarch64_sp_align' into 'master'

aarch64: align sp in _start

See merge request redox-os/relibc!412

src/crt0/src/lib.rs

@@ -11,6 +11,7 @@ global_asm!(
     .globl _start
 _start:
     mov x0, sp
+    and sp, x0, #0xfffffffffffffff0 //align sp
     bl relibc_start
 "
 );

src/ld_so/src/lib.rs

@@ -9,6 +9,7 @@ global_asm!(
 .globl _start
 _start:
     mov x0, sp
+    and sp, x0, #0xfffffffffffffff0 //align sp
     bl relibc_ld_so_start
     # TODO: aarch64
     udf #0