Add cfi directives to x86 syscalls.

Modify the syscalls script to generate the cfi directives for x86
syscalls.

Update the x86 syscalls.

Change-Id: Ia1993dc714a7e79f917087fff8200e9a02c52603
diff --git a/libc/arch-x86/syscalls/timerfd_create.S b/libc/arch-x86/syscalls/timerfd_create.S
index 8546c34..33b2980 100644
--- a/libc/arch-x86/syscalls/timerfd_create.S
+++ b/libc/arch-x86/syscalls/timerfd_create.S
@@ -5,6 +5,9 @@
 ENTRY(timerfd_create)
     pushl   %ebx
     pushl   %ecx
+    .cfi_def_cfa_offset 8
+    .cfi_rel_offset ebx, 0
+    .cfi_rel_offset ecx, 4
     mov     12(%esp), %ebx
     mov     16(%esp), %ecx
     movl    $__NR_timerfd_create, %eax