Support 32-bit ARM vdso.

Linux 4.1 added this.

Bug: http://b/19198045
Change-Id: I28be802ff403a61dd6733a001411b3ff05fef5a5
diff --git a/libc/arch-arm/syscalls/__clock_gettime.S b/libc/arch-arm/syscalls/__clock_gettime.S
new file mode 100644
index 0000000..30eff03
--- /dev/null
+++ b/libc/arch-arm/syscalls/__clock_gettime.S
@@ -0,0 +1,16 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(__clock_gettime)
+    mov     ip, r7
+    .cfi_register r7, ip
+    ldr     r7, =__NR_clock_gettime
+    swi     #0
+    mov     r7, ip
+    .cfi_restore r7
+    cmn     r0, #(MAX_ERRNO + 1)
+    bxls    lr
+    neg     r0, r0
+    b       __set_errno_internal
+END(__clock_gettime)