Fix incorrect relocations for x86.

These calls were not going through the PLT like they should have been.

Bug: 16853291
Change-Id: Id70488b077256a70137c4417f21be2c2d1d4341c
diff --git a/libc/arch-x86/syscalls/__sched_getaffinity.S b/libc/arch-x86/syscalls/__sched_getaffinity.S
index e7cb8f1..fe0b2f6 100644
--- a/libc/arch-x86/syscalls/__sched_getaffinity.S
+++ b/libc/arch-x86/syscalls/__sched_getaffinity.S
@@ -21,7 +21,7 @@
     jb      1f
     negl    %eax
     pushl   %eax
-    call    __set_errno
+    call    PIC_PLT(__set_errno)
     addl    $4, %esp
 1:
     popl    %edx