syscall: remove "use" function and calls from generated code.

Update syscall code generators to set build tags.

Regenerate zsyscall files, which makes the following changes:
- remove calls to "use"
- update build tags, adding missing ones in some cases
- "stat" renamed to "st" in some cases
- "libc_Utimes" renamed "libc_utimes" in one case

I'll mirror this change to x/sys/unix once committed.

Change-Id: Ic07e0ae1433dd133eb57e8dd2a3b86a62aab4eda
Reviewed-on: https://go-review.googlesource.com/36616
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/syscall/zsyscall_netbsd_386.go b/src/syscall/zsyscall_netbsd_386.go
index 61b52cd..ec32d9c 100644
--- a/src/syscall/zsyscall_netbsd_386.go
+++ b/src/syscall/zsyscall_netbsd_386.go
@@ -1,7 +1,7 @@
-// mksyscall.pl -l32 -netbsd syscall_bsd.go syscall_netbsd.go syscall_netbsd_386.go
+// mksyscall.pl -l32 -netbsd -tags netbsd,386 syscall_bsd.go syscall_netbsd.go syscall_netbsd_386.go
 // MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
 
-// +build 386,netbsd
+// +build netbsd,386
 
 package syscall
 
@@ -217,7 +217,6 @@
 		_p0 = unsafe.Pointer(&_zero)
 	}
 	_, _, e1 := Syscall6(SYS___SYSCTL, uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	use(_p0)
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -233,7 +232,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_UTIMES, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(timeval)), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -299,7 +297,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_ACCESS, uintptr(unsafe.Pointer(_p0)), uintptr(mode), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -325,7 +322,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_CHDIR, uintptr(unsafe.Pointer(_p0)), 0, 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -341,7 +337,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_CHFLAGS, uintptr(unsafe.Pointer(_p0)), uintptr(flags), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -357,7 +352,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_CHMOD, uintptr(unsafe.Pointer(_p0)), uintptr(mode), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -373,7 +367,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_CHOWN, uintptr(unsafe.Pointer(_p0)), uintptr(uid), uintptr(gid))
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -389,7 +382,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_CHROOT, uintptr(unsafe.Pointer(_p0)), 0, 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -682,7 +674,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_LCHOWN, uintptr(unsafe.Pointer(_p0)), uintptr(uid), uintptr(gid))
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -703,8 +694,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_LINK, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_p1)), 0)
-	use(unsafe.Pointer(_p0))
-	use(unsafe.Pointer(_p1))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -730,7 +719,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_LSTAT, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -746,7 +734,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_MKDIR, uintptr(unsafe.Pointer(_p0)), uintptr(mode), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -762,7 +749,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_MKFIFO, uintptr(unsafe.Pointer(_p0)), uintptr(mode), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -778,7 +764,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_MKNOD, uintptr(unsafe.Pointer(_p0)), uintptr(mode), uintptr(dev))
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -804,7 +789,6 @@
 		return
 	}
 	r0, _, e1 := Syscall(SYS_OPEN, uintptr(unsafe.Pointer(_p0)), uintptr(mode), uintptr(perm))
-	use(unsafe.Pointer(_p0))
 	fd = int(r0)
 	if e1 != 0 {
 		err = errnoErr(e1)
@@ -821,7 +805,6 @@
 		return
 	}
 	r0, _, e1 := Syscall(SYS_PATHCONF, uintptr(unsafe.Pointer(_p0)), uintptr(name), 0)
-	use(unsafe.Pointer(_p0))
 	val = int(r0)
 	if e1 != 0 {
 		err = errnoErr(e1)
@@ -895,7 +878,6 @@
 		_p1 = unsafe.Pointer(&_zero)
 	}
 	r0, _, e1 := Syscall(SYS_READLINK, uintptr(unsafe.Pointer(_p0)), uintptr(_p1), uintptr(len(buf)))
-	use(unsafe.Pointer(_p0))
 	n = int(r0)
 	if e1 != 0 {
 		err = errnoErr(e1)
@@ -917,8 +899,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_RENAME, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_p1)), 0)
-	use(unsafe.Pointer(_p0))
-	use(unsafe.Pointer(_p1))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -934,7 +914,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_REVOKE, uintptr(unsafe.Pointer(_p0)), 0, 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -950,7 +929,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_RMDIR, uintptr(unsafe.Pointer(_p0)), 0, 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -1098,7 +1076,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_STAT, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(stat)), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -1119,8 +1096,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_SYMLINK, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_p1)), 0)
-	use(unsafe.Pointer(_p0))
-	use(unsafe.Pointer(_p1))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -1146,7 +1121,6 @@
 		return
 	}
 	_, _, e1 := Syscall6(SYS_TRUNCATE, uintptr(unsafe.Pointer(_p0)), 0, uintptr(length), uintptr(length>>32), 0, 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -1170,7 +1144,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_UNLINK, uintptr(unsafe.Pointer(_p0)), 0, 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}
@@ -1186,7 +1159,6 @@
 		return
 	}
 	_, _, e1 := Syscall(SYS_UNMOUNT, uintptr(unsafe.Pointer(_p0)), uintptr(flags), 0)
-	use(unsafe.Pointer(_p0))
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}