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/perf_event_open.S b/libc/arch-x86/syscalls/perf_event_open.S
index 931282a..ebbe1f0 100644
--- a/libc/arch-x86/syscalls/perf_event_open.S
+++ b/libc/arch-x86/syscalls/perf_event_open.S
@@ -8,6 +8,12 @@
     pushl   %edx
     pushl   %esi
     pushl   %edi
+    .cfi_def_cfa_offset 20
+    .cfi_rel_offset ebx, 0
+    .cfi_rel_offset ecx, 4
+    .cfi_rel_offset edx, 8
+    .cfi_rel_offset esi, 12
+    .cfi_rel_offset edi, 16
     mov     24(%esp), %ebx
     mov     28(%esp), %ecx
     mov     32(%esp), %edx