Use ALIAS_SYMBOL for assembler aliasing.

Change-Id: I8d04d2da0a1ac440cc9044fc819c9a8eda5ff17d
diff --git a/libc/arch-arm64/bionic/setjmp.S b/libc/arch-arm64/bionic/setjmp.S
index 6e119dc..ba0a226 100644
--- a/libc/arch-arm64/bionic/setjmp.S
+++ b/libc/arch-arm64/bionic/setjmp.S
@@ -146,7 +146,5 @@
   ret
 END(siglongjmp)
 
-  .globl longjmp
-  .equ longjmp, siglongjmp
-  .globl _longjmp
-  .equ _longjmp, siglongjmp
+ALIAS_SYMBOL(longjmp, siglongjmp)
+ALIAS_SYMBOL(_longjmp, siglongjmp)