unix: define PerfBitWriteBackward

Change-Id: I0b95006039b4efcd0094ba96281100abeafc993e
GitHub-Last-Rev: 43383aac9080b35052bc5d10c783474f7614b33d
GitHub-Pull-Request: golang/sys#149
Reviewed-on: https://go-review.googlesource.com/c/sys/+/473135
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>

unix/linux/types.go

diff --git a/unix/linux/types.go b/unix/linux/types.go
index 3a564a1..6714533 100644
--- a/unix/linux/types.go
+++ b/unix/linux/types.go
@@ -1115,6 +1115,7 @@
 	PerfBitCommExec                      = CBitFieldMaskBit24
 	PerfBitUseClockID                    = CBitFieldMaskBit25
 	PerfBitContextSwitch                 = CBitFieldMaskBit26
+	PerfBitWriteBackward                 = CBitFieldMaskBit27
 )
 
 // generated by:

unix/ztypes_linux.go

diff --git a/unix/ztypes_linux.go b/unix/ztypes_linux.go
index 65155b3..ca84727 100644
--- a/unix/ztypes_linux.go
+++ b/unix/ztypes_linux.go
@@ -1067,6 +1067,7 @@
 	PerfBitCommExec                      = CBitFieldMaskBit24
 	PerfBitUseClockID                    = CBitFieldMaskBit25
 	PerfBitContextSwitch                 = CBitFieldMaskBit26
+	PerfBitWriteBackward                 = CBitFieldMaskBit27
 )
 
 const (