[PATCH] aarch64 sigreturn.c

[enh]

i'm not sure whether you intended these to go in a header file, but
sys_sigreturn doesn't compile for me because of missing declarations
for globals from syscall.c. (Android builds with more warnings as
errors.)

diff --git a/sigreturn.c b/sigreturn.c
index 365ef1a..0dc2005 100644
--- a/sigreturn.c
+++ b/sigreturn.c
@@ -17,6 +17,9 @@ int
 sys_sigreturn(struct tcb *tcp)
 {
 #if defined AARCH64 || defined ARM
+ extern uint64_t *const aarch64_sp_ptr;
+ extern uint32_t *const arm_sp_ptr;
+
  if (entering(tcp)) {
 # define SIZEOF_STRUCT_SIGINFO 128
 # define SIZEOF_STRUCT_SIGCONTEXT (21 * 4)