unix: add Setxattr constants

Add the XATTR_CREATE and XATTR_REPLACE constants, to be used in the
flags parameter of Setxattr/Lsetxattr. See
http://man7.org/linux/man-pages/man2/setxattr.2.html

Fixes golang/go#14454

Change-Id: I868ac019fe3be755e0f6f8bff734f843ba602ee9
Reviewed-on: https://go-review.googlesource.com/46690
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/mkerrors.sh

@@ -153,6 +153,7 @@ struct ltchars {
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/socket.h>
+#include <sys/xattr.h>
 #include <linux/if.h>
 #include <linux/if_alg.h>
 #include <linux/if_arp.h>
@@ -404,6 +405,7 @@ ccflags="$@"
 		$2 ~ /^KEYCTL_/ ||
 		$2 ~ /^SPLICE_/ ||
 		$2 ~ /^(VM|VMADDR)_/ ||
+		$2 ~ /^XATTR_(CREATE|REPLACE)/ ||
 		$2 !~ "WMESGLEN" &&
 		$2 ~ /^W[A-Z0-9]+$/ ||
 		$2 ~ /^BLK[A-Z]*(GET$|SET$|BUF$|PART$|SIZE)/ {printf("\t%s = C.%s\n", $2, $2)}

unix/zerrors_linux_386.go

@@ -1788,6 +1788,8 @@ const (
 	WORDSIZE                             = 0x20
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_amd64.go

@@ -1789,6 +1789,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_arm.go

@@ -1793,6 +1793,8 @@ const (
 	WORDSIZE                             = 0x20
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_arm64.go

@@ -1778,6 +1778,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_mips.go

@@ -1793,6 +1793,8 @@ const (
 	WORDSIZE                             = 0x20
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_mips64.go

@@ -1793,6 +1793,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_mips64le.go

@@ -1793,6 +1793,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_mipsle.go

@@ -1793,6 +1793,8 @@ const (
 	WORDSIZE                             = 0x20
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )

unix/zerrors_linux_ppc64.go

@@ -1850,6 +1850,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4000
 	XTABS                                = 0xc00
 )

unix/zerrors_linux_ppc64le.go

@@ -1850,6 +1850,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4000
 	XTABS                                = 0xc00
 )

unix/zerrors_linux_s390x.go

@@ -1850,6 +1850,8 @@ const (
 	WORDSIZE                             = 0x40
 	WSTOPPED                             = 0x2
 	WUNTRACED                            = 0x2
+	XATTR_CREATE                         = 0x1
+	XATTR_REPLACE                        = 0x2
 	XCASE                                = 0x4
 	XTABS                                = 0x1800
 )