Make gensyscalls.py use the ALIAS_SYMBOL macro.

Change-Id: Ib94c0abb6fc85126ecc5ed3f1962b2b8b90b9952
diff --git a/libc/arch-x86_64/syscalls/getrlimit.S b/libc/arch-x86_64/syscalls/getrlimit.S
index 2d272a1..00ed08a 100644
--- a/libc/arch-x86_64/syscalls/getrlimit.S
+++ b/libc/arch-x86_64/syscalls/getrlimit.S
@@ -14,5 +14,4 @@
     ret
 END(getrlimit)
 
-    .globl getrlimit64
-    .equ getrlimit64, getrlimit
+ALIAS_SYMBOL(getrlimit64, getrlimit)