unix: add taskstats type and constants on Linux

Taskstats is a netlink-based interface for sending per-task and
per-process statistics from the kernel to userspace.

For more information, please see:
https://www.kernel.org/doc/Documentation/accounting/taskstats.txt.

Fixes golang/go#21616.

Change-Id: I7d4b8035aa8e993074d61911d9a8c3a3e61c9b2e
Reviewed-on: https://go-review.googlesource.com/59050
Run-TryBot: Matt Layher <mdlayher@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/unix/zerrors_linux_386.go b/unix/zerrors_linux_386.go
index a6b3b5f..c12bbb9 100644
--- a/unix/zerrors_linux_386.go
+++ b/unix/zerrors_linux_386.go
@@ -1626,6 +1626,12 @@
 	TAB2                                 = 0x1000
 	TAB3                                 = 0x1800
 	TABDLY                               = 0x1800
+	TASKSTATS_CMD_ATTR_MAX               = 0x4
+	TASKSTATS_CMD_MAX                    = 0x2
+	TASKSTATS_GENL_NAME                  = "TASKSTATS"
+	TASKSTATS_GENL_VERSION               = 0x1
+	TASKSTATS_TYPE_MAX                   = 0x6
+	TASKSTATS_VERSION                    = 0x8
 	TCFLSH                               = 0x540b
 	TCGETA                               = 0x5405
 	TCGETS                               = 0x5401
@@ -1765,6 +1771,7 @@
 	TIOCSWINSZ                           = 0x5414
 	TIOCVHANGUP                          = 0x5437
 	TOSTOP                               = 0x100
+	TS_COMM_LEN                          = 0x20
 	TUNATTACHFILTER                      = 0x400854d5
 	TUNDETACHFILTER                      = 0x400854d6
 	TUNGETFEATURES                       = 0x800454cf