Add extended attribute (xattr) system call wrappers to bionic.

The xattr system calls are required for the SE Android userspace in
order to get and set file security contexts.  In particular, libselinux
requires these calls.

Change-Id: I78f5eb3d8f3384aed0a5e7c6a6f001781d982017
diff --git a/libc/arch-x86/syscalls/fsetxattr.S b/libc/arch-x86/syscalls/fsetxattr.S
new file mode 100644
index 0000000..a70ca4f
--- /dev/null
+++ b/libc/arch-x86/syscalls/fsetxattr.S
@@ -0,0 +1,35 @@
+/* autogenerated by gensyscalls.py */
+#include <sys/linux-syscalls.h>
+
+    .text
+    .type fsetxattr, @function
+    .globl fsetxattr
+    .align 4
+
+fsetxattr:
+    pushl   %ebx
+    pushl   %ecx
+    pushl   %edx
+    pushl   %esi
+    pushl   %edi
+    mov     24(%esp), %ebx
+    mov     28(%esp), %ecx
+    mov     32(%esp), %edx
+    mov     36(%esp), %esi
+    mov     40(%esp), %edi
+    movl    $__NR_fsetxattr, %eax
+    int     $0x80
+    cmpl    $-129, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    addl    $4, %esp
+    orl     $-1, %eax
+1:
+    popl    %edi
+    popl    %esi
+    popl    %edx
+    popl    %ecx
+    popl    %ebx
+    ret