<sched.h>: Add sched_getcpu() and cpu_set_t

This adds the cpu_set_t type definition and related functions
and macros used to handle CPU thread affinity.

  sched_getcpu()
  sched_setaffinity()
  sched_getaffinity()

Change-Id: If382ecafde8926341a88478062b275553645065b
diff --git a/libc/arch-x86/syscalls/sched_setaffinity.S b/libc/arch-x86/syscalls/sched_setaffinity.S
new file mode 100644
index 0000000..5fa51ef
--- /dev/null
+++ b/libc/arch-x86/syscalls/sched_setaffinity.S
@@ -0,0 +1,29 @@
+/* autogenerated by gensyscalls.py */
+#include <sys/linux-syscalls.h>
+
+    .text
+    .type sched_setaffinity, @function
+    .globl sched_setaffinity
+    .align 4
+
+sched_setaffinity:
+    pushl   %ebx
+    pushl   %ecx
+    pushl   %edx
+    mov     16(%esp), %ebx
+    mov     20(%esp), %ecx
+    mov     24(%esp), %edx
+    movl    $__NR_sched_setaffinity, %eax
+    int     $0x80
+    cmpl    $-129, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    addl    $4, %esp
+    orl     $-1, %eax
+1:
+    popl    %edx
+    popl    %ecx
+    popl    %ebx
+    ret