Make gensyscalls.py use the ALIAS_SYMBOL macro.

Change-Id: Ib94c0abb6fc85126ecc5ed3f1962b2b8b90b9952
diff --git a/libc/arch-arm64/syscalls/fallocate.S b/libc/arch-arm64/syscalls/fallocate.S
index ef3d4a4..d42a0ba 100644
--- a/libc/arch-arm64/syscalls/fallocate.S
+++ b/libc/arch-arm64/syscalls/fallocate.S
@@ -13,5 +13,4 @@
     ret
 END(fallocate)
 
-    .globl fallocate64
-    .equ fallocate64, fallocate
+ALIAS_SYMBOL(fallocate64, fallocate)