syscall: add constants for flock() system call under Linux.

The values have been generated only for the i386 and amd64 architectures.

R=golang-dev, mikioh.mikioh, dsymonds
CC=bradfitz, dsymonds, golang-dev
https://golang.org/cl/5452060

src/pkg/syscall/mkerrors.sh

@@ -108,6 +108,7 @@ includes_OpenBSD='
 
 includes='
 #include <sys/types.h>
+#include <sys/file.h>
 #include <fcntl.h>
 #include <dirent.h>
 #include <sys/socket.h>
@@ -153,6 +154,7 @@ ccflags="$@"
 		$2 ~ /^E[A-Z0-9_]+$/ ||
 		$2 ~ /^SIG[^_]/ ||
 		$2 ~ /^IN_/ ||
+		$2 ~ /^LOCK_(SH|EX|NB|UN)$/ ||
 		$2 ~ /^(AF|SOCK|SO|SOL|IPPROTO|IP|IPV6|TCP|EVFILT|EV|SHUT|PROT|MAP|PACKET|MSG|SCM|MCL|DT|MADV)_/ ||
 		$2 == "SOMAXCONN" ||
 		$2 == "NAME_MAX" ||

src/pkg/syscall/zerrors_linux_386.go

@@ -478,6 +478,10 @@ const (
 	LINUX_REBOOT_CMD_SW_SUSPEND      = 0xd000fce2
 	LINUX_REBOOT_MAGIC1              = 0xfee1dead
 	LINUX_REBOOT_MAGIC2              = 0x28121969
+	LOCK_EX                          = 0x2
+	LOCK_NB                          = 0x4
+	LOCK_SH                          = 0x1
+	LOCK_UN                          = 0x8
 	MADV_DOFORK                      = 0xb
 	MADV_DONTFORK                    = 0xa
 	MADV_DONTNEED                    = 0x4

src/pkg/syscall/zerrors_linux_amd64.go

@@ -478,6 +478,10 @@ const (
 	LINUX_REBOOT_CMD_SW_SUSPEND      = 0xd000fce2
 	LINUX_REBOOT_MAGIC1              = 0xfee1dead
 	LINUX_REBOOT_MAGIC2              = 0x28121969
+	LOCK_EX                          = 0x2
+	LOCK_NB                          = 0x4
+	LOCK_SH                          = 0x1
+	LOCK_UN                          = 0x8
 	MADV_DOFORK                      = 0xb
 	MADV_DONTFORK                    = 0xa
 	MADV_DONTNEED                    = 0x4