libc: add swapon and swapoff syscalls

Change-Id: Ie79dc8e3f2ff1cd427dd6d95e3850920c4b407b0
Signed-off-by: Rom Lemarchand <romlem@google.com>
diff --git a/libc/arch-x86/syscalls/swapoff.S b/libc/arch-x86/syscalls/swapoff.S
new file mode 100644
index 0000000..f2d6ddb
--- /dev/null
+++ b/libc/arch-x86/syscalls/swapoff.S
@@ -0,0 +1,21 @@
+/* autogenerated by gensyscalls.py */
+#include <linux/err.h>
+#include <machine/asm.h>
+#include <asm/unistd.h>
+
+ENTRY(swapoff)
+    pushl   %ebx
+    mov     8(%esp), %ebx
+    movl    $__NR_swapoff, %eax
+    int     $0x80
+    cmpl    $-MAX_ERRNO, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    addl    $4, %esp
+    orl     $-1, %eax
+1:
+    popl    %ebx
+    ret
+END(swapoff)