Add {get,set}domainname(2)

{get,set}domainname aren't in POSIX but are widely-implemented
extensions.

The Linux kernel provides a setdomainname syscall but not a symmetric
getdomainname syscall, since it expects userspace to get the domain name
from uname(2).

Change-Id: I96726c242f4bb646c130b361688328b0b97269a0
Signed-off-by: Greg Hackmann <ghackmann@google.com>
diff --git a/libc/arch-arm/syscalls/setdomainname.S b/libc/arch-arm/syscalls/setdomainname.S
new file mode 100644
index 0000000..20f1f6f
--- /dev/null
+++ b/libc/arch-arm/syscalls/setdomainname.S
@@ -0,0 +1,14 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(setdomainname)
+    mov     ip, r7
+    ldr     r7, =__NR_setdomainname
+    swi     #0
+    mov     r7, ip
+    cmn     r0, #(MAX_ERRNO + 1)
+    bxls    lr
+    neg     r0, r0
+    b       __set_errno_internal
+END(setdomainname)