Add unshare() syscall.

(cherry-pick of 5467f25f82934d611c60f8bc57a05114f3c1bea0.)

Bug: 6925012
Change-Id: Ic5ea2fbd606311087de05d7a3594df2fa9b2fef9
diff --git a/libc/arch-mips/syscalls/unshare.S b/libc/arch-mips/syscalls/unshare.S
new file mode 100644
index 0000000..11af354
--- /dev/null
+++ b/libc/arch-mips/syscalls/unshare.S
@@ -0,0 +1,22 @@
+/* autogenerated by gensyscalls.py */
+#include <sys/linux-syscalls.h>
+    .text
+    .globl unshare
+    .align 4
+    .ent unshare
+
+unshare:
+    .set noreorder
+    .cpload $t9
+    li $v0, __NR_unshare
+    syscall
+    bnez $a3, 1f
+    move $a0, $v0
+    j $ra
+    nop
+1:
+    la $t9,__set_errno
+    j $t9
+    nop
+    .set reorder
+    .end unshare