diff --git a/src/cmd/vendor/golang.org/x/sys/unix/example_exec_test.go b/src/cmd/vendor/golang.org/x/sys/unix/example_exec_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..bb4d3bf5da9ad588c55442719d46c3ae2181626d
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/sys/unix/example_exec_test.go
@@ -0,0 +1,19 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package unix_test
+
+import (
+	"log"
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func ExampleExec() {
+	err := unix.Exec("/bin/ls", []string{"ls", "-al"}, os.Environ())
+	log.Fatal(err)
+}
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/example_test.go b/src/cmd/vendor/golang.org/x/sys/unix/example_flock_test.go
similarity index 75%
rename from src/cmd/vendor/golang.org/x/sys/unix/example_test.go
rename to src/cmd/vendor/golang.org/x/sys/unix/example_flock_test.go
index ae008f5ba6cc7d2771fe1b838ba9d0d5b8782e80..6c9174859e80bb74776b891a5ff570c3ccf0d544 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/example_test.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/example_flock_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package unix_test
 
@@ -13,11 +13,6 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func ExampleExec() {
-	err := unix.Exec("/bin/ls", []string{"ls", "-al"}, os.Environ())
-	log.Fatal(err)
-}
-
 func ExampleFlock() {
 	f, _ := os.Create("example.lock")
 	if err := unix.Flock(int(f.Fd()), unix.LOCK_EX); err != nil {
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/mksyscall.pl b/src/cmd/vendor/golang.org/x/sys/unix/mksyscall.pl
deleted file mode 100755
index 1f6b926f8c64cb0fbfa417e78c5fa8fee650410a..0000000000000000000000000000000000000000
--- a/src/cmd/vendor/golang.org/x/sys/unix/mksyscall.pl
+++ /dev/null
@@ -1,341 +0,0 @@
-#!/usr/bin/env perl
-# Copyright 2009 The Go Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style
-# license that can be found in the LICENSE file.
-
-# This program reads a file containing function prototypes
-# (like syscall_darwin.go) and generates system call bodies.
-# The prototypes are marked by lines beginning with "//sys"
-# and read like func declarations if //sys is replaced by func, but:
-#	* The parameter lists must give a name for each argument.
-#	  This includes return parameters.
-#	* The parameter lists must give a type for each argument:
-#	  the (x, y, z int) shorthand is not allowed.
-#	* If the return parameter is an error number, it must be named errno.
-
-# A line beginning with //sysnb is like //sys, except that the
-# goroutine will not be suspended during the execution of the system
-# call.  This must only be used for system calls which can never
-# block, as otherwise the system call could cause all goroutines to
-# hang.
-
-use strict;
-
-my $cmdline = "mksyscall.pl " . join(' ', @ARGV);
-my $errors = 0;
-my $_32bit = "";
-my $plan9 = 0;
-my $openbsd = 0;
-my $netbsd = 0;
-my $dragonfly = 0;
-my $arm = 0; # 64-bit value should use (even, odd)-pair
-my $tags = "";  # build tags
-
-if($ARGV[0] eq "-b32") {
-	$_32bit = "big-endian";
-	shift;
-} elsif($ARGV[0] eq "-l32") {
-	$_32bit = "little-endian";
-	shift;
-}
-if($ARGV[0] eq "-plan9") {
-	$plan9 = 1;
-	shift;
-}
-if($ARGV[0] eq "-openbsd") {
-	$openbsd = 1;
-	shift;
-}
-if($ARGV[0] eq "-netbsd") {
-	$netbsd = 1;
-	shift;
-}
-if($ARGV[0] eq "-dragonfly") {
-	$dragonfly = 1;
-	shift;
-}
-if($ARGV[0] eq "-arm") {
-	$arm = 1;
-	shift;
-}
-if($ARGV[0] eq "-tags") {
-	shift;
-	$tags = $ARGV[0];
-	shift;
-}
-
-if($ARGV[0] =~ /^-/) {
-	print STDERR "usage: mksyscall.pl [-b32 | -l32] [-tags x,y] [file ...]\n";
-	exit 1;
-}
-
-# Check that we are using the new build system if we should
-if($ENV{'GOOS'} eq "linux" && $ENV{'GOARCH'} ne "sparc64") {
-	if($ENV{'GOLANG_SYS_BUILD'} ne "docker") {
-		print STDERR "In the new build system, mksyscall should not be called directly.\n";
-		print STDERR "See README.md\n";
-		exit 1;
-	}
-}
-
-
-sub parseparamlist($) {
-	my ($list) = @_;
-	$list =~ s/^\s*//;
-	$list =~ s/\s*$//;
-	if($list eq "") {
-		return ();
-	}
-	return split(/\s*,\s*/, $list);
-}
-
-sub parseparam($) {
-	my ($p) = @_;
-	if($p !~ /^(\S*) (\S*)$/) {
-		print STDERR "$ARGV:$.: malformed parameter: $p\n";
-		$errors = 1;
-		return ("xx", "int");
-	}
-	return ($1, $2);
-}
-
-my $text = "";
-while(<>) {
-	chomp;
-	s/\s+/ /g;
-	s/^\s+//;
-	s/\s+$//;
-	my $nonblock = /^\/\/sysnb /;
-	next if !/^\/\/sys / && !$nonblock;
-
-	# Line must be of the form
-	#	func Open(path string, mode int, perm int) (fd int, errno error)
-	# Split into name, in params, out params.
-	if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*((?i)SYS_[A-Z0-9_]+))?$/) {
-		print STDERR "$ARGV:$.: malformed //sys declaration\n";
-		$errors = 1;
-		next;
-	}
-	my ($func, $in, $out, $sysname) = ($2, $3, $4, $5);
-
-	# Split argument lists on comma.
-	my @in = parseparamlist($in);
-	my @out = parseparamlist($out);
-
-	# Try in vain to keep people from editing this file.
-	# The theory is that they jump into the middle of the file
-	# without reading the header.
-	$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
-
-	# Go function header.
-	my $out_decl = @out ? sprintf(" (%s)", join(', ', @out)) : "";
-	$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out_decl;
-
-	# Check if err return available
-	my $errvar = "";
-	foreach my $p (@out) {
-		my ($name, $type) = parseparam($p);
-		if($type eq "error") {
-			$errvar = $name;
-			last;
-		}
-	}
-
-	# Prepare arguments to Syscall.
-	my @args = ();
-	my $n = 0;
-	foreach my $p (@in) {
-		my ($name, $type) = parseparam($p);
-		if($type =~ /^\*/) {
-			push @args, "uintptr(unsafe.Pointer($name))";
-		} elsif($type eq "string" && $errvar ne "") {
-			$text .= "\tvar _p$n *byte\n";
-			$text .= "\t_p$n, $errvar = BytePtrFromString($name)\n";
-			$text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n";
-			push @args, "uintptr(unsafe.Pointer(_p$n))";
-			$n++;
-		} elsif($type eq "string") {
-			print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n";
-			$text .= "\tvar _p$n *byte\n";
-			$text .= "\t_p$n, _ = BytePtrFromString($name)\n";
-			push @args, "uintptr(unsafe.Pointer(_p$n))";
-			$n++;
-		} elsif($type =~ /^\[\](.*)/) {
-			# Convert slice into pointer, length.
-			# Have to be careful not to take address of &a[0] if len == 0:
-			# pass dummy pointer in that case.
-			# Used to pass nil, but some OSes or simulators reject write(fd, nil, 0).
-			$text .= "\tvar _p$n unsafe.Pointer\n";
-			$text .= "\tif len($name) > 0 {\n\t\t_p$n = unsafe.Pointer(\&${name}[0])\n\t}";
-			$text .= " else {\n\t\t_p$n = unsafe.Pointer(&_zero)\n\t}";
-			$text .= "\n";
-			push @args, "uintptr(_p$n)", "uintptr(len($name))";
-			$n++;
-		} elsif($type eq "int64" && ($openbsd || $netbsd)) {
-			push @args, "0";
-			if($_32bit eq "big-endian") {
-				push @args, "uintptr($name>>32)", "uintptr($name)";
-			} elsif($_32bit eq "little-endian") {
-				push @args, "uintptr($name)", "uintptr($name>>32)";
-			} else {
-				push @args, "uintptr($name)";
-			}
-		} elsif($type eq "int64" && $dragonfly) {
-			if ($func !~ /^extp(read|write)/i) {
-				push @args, "0";
-			}
-			if($_32bit eq "big-endian") {
-				push @args, "uintptr($name>>32)", "uintptr($name)";
-			} elsif($_32bit eq "little-endian") {
-				push @args, "uintptr($name)", "uintptr($name>>32)";
-			} else {
-				push @args, "uintptr($name)";
-			}
-		} elsif($type eq "int64" && $_32bit ne "") {
-			if(@args % 2 && $arm) {
-				# arm abi specifies 64-bit argument uses
-				# (even, odd) pair
-				push @args, "0"
-			}
-			if($_32bit eq "big-endian") {
-				push @args, "uintptr($name>>32)", "uintptr($name)";
-			} else {
-				push @args, "uintptr($name)", "uintptr($name>>32)";
-			}
-		} else {
-			push @args, "uintptr($name)";
-		}
-	}
-
-	# Determine which form to use; pad args with zeros.
-	my $asm = "Syscall";
-	if ($nonblock) {
-		if ($errvar eq "" && $ENV{'GOOS'} eq "linux") {
-			$asm = "RawSyscallNoError";
-		} else {
-			$asm = "RawSyscall";
-		}
-	} else {
-		if ($errvar eq "" && $ENV{'GOOS'} eq "linux") {
-			$asm = "SyscallNoError";
-		}
-	}
-	if(@args <= 3) {
-		while(@args < 3) {
-			push @args, "0";
-		}
-	} elsif(@args <= 6) {
-		$asm .= "6";
-		while(@args < 6) {
-			push @args, "0";
-		}
-	} elsif(@args <= 9) {
-		$asm .= "9";
-		while(@args < 9) {
-			push @args, "0";
-		}
-	} else {
-		print STDERR "$ARGV:$.: too many arguments to system call\n";
-	}
-
-	# System call number.
-	if($sysname eq "") {
-		$sysname = "SYS_$func";
-		$sysname =~ s/([a-z])([A-Z])/${1}_$2/g;	# turn FooBar into Foo_Bar
-		$sysname =~ y/a-z/A-Z/;
-	}
-
-	# Actual call.
-	my $args = join(', ', @args);
-	my $call = "$asm($sysname, $args)";
-
-	# Assign return values.
-	my $body = "";
-	my @ret = ("_", "_", "_");
-	my $do_errno = 0;
-	for(my $i=0; $i<@out; $i++) {
-		my $p = $out[$i];
-		my ($name, $type) = parseparam($p);
-		my $reg = "";
-		if($name eq "err" && !$plan9) {
-			$reg = "e1";
-			$ret[2] = $reg;
-			$do_errno = 1;
-		} elsif($name eq "err" && $plan9) {
-			$ret[0] = "r0";
-			$ret[2] = "e1";
-			next;
-		} else {
-			$reg = sprintf("r%d", $i);
-			$ret[$i] = $reg;
-		}
-		if($type eq "bool") {
-			$reg = "$reg != 0";
-		}
-		if($type eq "int64" && $_32bit ne "") {
-			# 64-bit number in r1:r0 or r0:r1.
-			if($i+2 > @out) {
-				print STDERR "$ARGV:$.: not enough registers for int64 return\n";
-			}
-			if($_32bit eq "big-endian") {
-				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1);
-			} else {
-				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i);
-			}
-			$ret[$i] = sprintf("r%d", $i);
-			$ret[$i+1] = sprintf("r%d", $i+1);
-		}
-		if($reg ne "e1" || $plan9) {
-			$body .= "\t$name = $type($reg)\n";
-		}
-	}
-	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
-		$text .= "\t$call\n";
-	} else {
-		if ($errvar eq "" && $ENV{'GOOS'} eq "linux") {
-			# raw syscall without error on Linux, see golang.org/issue/22924
-			$text .= "\t$ret[0], $ret[1] := $call\n";
-		} else {
-			$text .= "\t$ret[0], $ret[1], $ret[2] := $call\n";
-		}
-	}
-	$text .= $body;
-
-	if ($plan9 && $ret[2] eq "e1") {
-		$text .= "\tif int32(r0) == -1 {\n";
-		$text .= "\t\terr = e1\n";
-		$text .= "\t}\n";
-	} elsif ($do_errno) {
-		$text .= "\tif e1 != 0 {\n";
-		$text .= "\t\terr = errnoErr(e1)\n";
-		$text .= "\t}\n";
-	}
-	$text .= "\treturn\n";
-	$text .= "}\n\n";
-}
-
-chomp $text;
-chomp $text;
-
-if($errors) {
-	exit 1;
-}
-
-print <<EOF;
-// $cmdline
-// Code generated by the command above; see README.md. DO NOT EDIT.
-
-// +build $tags
-
-package unix
-
-import (
-	"syscall"
-	"unsafe"
-)
-
-var _ syscall.Errno
-
-$text
-EOF
-exit 0;
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/sockcmsg_unix.go b/src/cmd/vendor/golang.org/x/sys/unix/sockcmsg_unix.go
index 52b6e225e9ee9c4194afa2b2d96d706d101e8fd0..5f9ae233a7a62af88a77d9d0142aa78f546394e2 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/sockcmsg_unix.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/sockcmsg_unix.go
@@ -13,28 +13,26 @@ import (
 	"unsafe"
 )
 
-var cmsgAlign = SizeofPtr
+// Round the length of a raw sockaddr up to align it properly.
+func cmsgAlignOf(salen int) int {
+	salign := SizeofPtr
 
-func init() {
 	switch runtime.GOOS {
 	case "darwin", "dragonfly", "solaris":
 		// NOTE: It seems like 64-bit Darwin, DragonFly BSD and
 		// Solaris kernels still require 32-bit aligned access to
 		// network subsystem.
 		if SizeofPtr == 8 {
-			cmsgAlign = 4
+			salign = 4
 		}
 	case "openbsd":
 		// OpenBSD armv7 requires 64-bit alignment.
 		if runtime.GOARCH == "arm" {
-			cmsgAlign = 8
+			salign = 8
 		}
 	}
-}
 
-// Round the length of a raw sockaddr up to align it properly.
-func cmsgAlignOf(salen int) int {
-	return (salen + cmsgAlign - 1) & ^(cmsgAlign - 1)
+	return (salen + salign - 1) & ^(salign - 1)
 }
 
 // CmsgLen returns the value to store in the Len field of the Cmsghdr
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/syscall_aix.go b/src/cmd/vendor/golang.org/x/sys/unix/syscall_aix.go
index f8eac1742853d517ea6d1586d8d8a518d92240bf..992a8ea0f785bb331a969b088c2fedb280f9a69f 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/syscall_aix.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/syscall_aix.go
@@ -13,10 +13,7 @@
 
 package unix
 
-import (
-	"syscall"
-	"unsafe"
-)
+import "unsafe"
 
 /*
  * Wrapped
@@ -385,10 +382,6 @@ func IoctlGetTermios(fd int, req uint) (*Termios, error) {
 
 //sys	fcntl(fd int, cmd int, arg int) (val int, err error)
 
-func Flock(fd int, how int) (err error) {
-	return syscall.Flock(fd, how)
-}
-
 /*
  * Direct access
  */
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go b/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go
index 3ec7a9329d2984d5d19f56d3c093351b08f64620..ad2bd2582f3bbe1365ad1406f70320161392cbe7 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux_arm.go
@@ -257,3 +257,11 @@ func Poll(fds []PollFd, timeout int) (n int, err error) {
 	}
 	return poll(&fds[0], len(fds), timeout)
 }
+
+//sys	armSyncFileRange(fd int, flags int, off int64, n int64) (err error) = SYS_ARM_SYNC_FILE_RANGE
+
+func SyncFileRange(fd int, off int64, n int64, flags int) error {
+	// The sync_file_range and arm_sync_file_range syscalls differ only in the
+	// order of their arguments.
+	return armSyncFileRange(fd, flags, off, n)
+}
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/zsyscall_linux_arm.go b/src/cmd/vendor/golang.org/x/sys/unix/zsyscall_linux_arm.go
index 75db4c0c1579ce24648e05826ab14f9c09f6daca..012261ad549f5fe31d3dbb2c1d4fe059864e4eca 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/zsyscall_linux_arm.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/zsyscall_linux_arm.go
@@ -2282,3 +2282,13 @@ func poll(fds *PollFd, nfds int, timeout int) (n int, err error) {
 	}
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func armSyncFileRange(fd int, flags int, off int64, n int64) (err error) {
+	_, _, e1 := Syscall6(SYS_ARM_SYNC_FILE_RANGE, uintptr(fd), uintptr(flags), uintptr(off), uintptr(off>>32), uintptr(n), uintptr(n>>32))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
diff --git a/src/cmd/vendor/vendor.json b/src/cmd/vendor/vendor.json
index 7cfda75a5edbc449ff5000e1e9dd6fc64e041ba8..1dcf16d5a957958d0c2408b26130b6a3701ebae9 100644
--- a/src/cmd/vendor/vendor.json
+++ b/src/cmd/vendor/vendor.json
@@ -131,10 +131,10 @@
 			"revisionTime": "2018-05-24T11:38:20Z"
 		},
 		{
-			"checksumSHA1": "6AYGJTfvoIblJAxlh0AEIQrRKgo=",
+			"checksumSHA1": "rx5/IrpHIVwz6KnAeqbTGHZe040=",
 			"path": "golang.org/x/sys/unix",
-			"revision": "b05ddf57801d2239d6ab0ee35f9d981e0420f4ac",
-			"revisionTime": "2018-12-11T16:24:22Z"
+			"revision": "4d1cda033e0619309c606fc686de3adcf599539e",
+			"revisionTime": "2018-12-13T07:38:38Z"
 		},
 		{
 			"checksumSHA1": "s+lofQ+SCdhmy0cQp9FpdQncuuI=",