Fix x86 cfi directives for syscalls.

The syscall generation always used 4 bytes for each push cfi directive.
However, the first push should always use an offset of 8 bytes, each
subsequent push after that is only 4 bytes though.

Change-Id: Ibaabd107f399ef67010b9a08213783957c2f74a9
diff --git a/libc/arch-x86/syscalls/__pselect6.S b/libc/arch-x86/syscalls/__pselect6.S
index 984a67e..9c66a3c 100644
--- a/libc/arch-x86/syscalls/__pselect6.S
+++ b/libc/arch-x86/syscalls/__pselect6.S
@@ -4,18 +4,23 @@
 
 ENTRY(__pselect6)
     pushl   %ebx
-    pushl   %ecx
-    pushl   %edx
-    pushl   %esi
-    pushl   %edi
-    pushl   %ebp
-    .cfi_def_cfa_offset 24
+    .cfi_def_cfa_offset 8
     .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
-    .cfi_rel_offset ebp, 20
+    pushl   %ecx
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset ecx, 0
+    pushl   %edx
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset edx, 0
+    pushl   %esi
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset esi, 0
+    pushl   %edi
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset edi, 0
+    pushl   %ebp
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset ebp, 0
     mov     28(%esp), %ebx
     mov     32(%esp), %ecx
     mov     36(%esp), %edx