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-x86/syscalls/__socket.S b/libc/arch-x86/syscalls/__socket.S
new file mode 100644
index 0000000..5e52d8f
--- /dev/null
+++ b/libc/arch-x86/syscalls/__socket.S
@@ -0,0 +1,27 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(__socket)
+    pushl   %ebx
+    pushl   %ecx
+    .cfi_def_cfa_offset 8
+    .cfi_rel_offset ebx, 0
+    .cfi_rel_offset ecx, 4
+    mov     $1, %ebx
+    mov     %esp, %ecx
+    addl    $12, %ecx
+    movl    $__NR_socketcall, %eax
+    int     $0x80
+    cmpl    $-MAX_ERRNO, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    addl    $4, %esp
+    orl     $-1, %eax
+1:
+    popl    %ecx
+    popl    %ebx
+    ret
+END(__socket)