Mark sockets on creation (socket()) and accept4().

Remove the separate syscall for accept() and implement it as accept4(..., 0).

Change-Id: Ib0b8f5d7c5013b91eae6bbc3847852eb355c7714
diff --git a/libc/arch-mips/syscalls/__socket.S b/libc/arch-mips/syscalls/__socket.S
new file mode 100644
index 0000000..6508911
--- /dev/null
+++ b/libc/arch-mips/syscalls/__socket.S
@@ -0,0 +1,19 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(__socket)
+    .set noreorder
+    .cpload t9
+    li v0, __NR_socket
+    syscall
+    bnez a3, 1f
+    move a0, v0
+    j ra
+    nop
+1:
+    la t9,__set_errno
+    j t9
+    nop
+    .set reorder
+END(__socket)