libc: add swapon and swapoff syscalls

Change-Id: Ie79dc8e3f2ff1cd427dd6d95e3850920c4b407b0
Signed-off-by: Rom Lemarchand <romlem@google.com>
diff --git a/libc/arch-x86/syscalls.mk b/libc/arch-x86/syscalls.mk
index 31eb930..11573de 100644
--- a/libc/arch-x86/syscalls.mk
+++ b/libc/arch-x86/syscalls.mk
@@ -130,6 +130,8 @@
 syscall_src += arch-x86/syscalls/lremovexattr.S
 syscall_src += arch-x86/syscalls/__statfs64.S
 syscall_src += arch-x86/syscalls/unshare.S
+syscall_src += arch-x86/syscalls/swapon.S
+syscall_src += arch-x86/syscalls/swapoff.S
 syscall_src += arch-x86/syscalls/pause.S
 syscall_src += arch-x86/syscalls/gettimeofday.S
 syscall_src += arch-x86/syscalls/settimeofday.S