unix: add marker comments to zsyscall_solaris_amd64.go

These marker comments are in every other zsyscall_*.go file generated by
mksyscall.pl and mksyscall_aix.pl. Also add them to the file generated
by mksyscall_solaris.pl.

Change-Id: Ic0ad5f28dd0a0934aa768f58ccc390b613a36abb
Reviewed-on: https://go-review.googlesource.com/c/141557
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/mksyscall_solaris.pl

@@ -92,6 +92,11 @@ while(<>) {
 	my @in = parseparamlist($in);
 	my @out = parseparamlist($out);
 
+	# Try in vain to keep people from editing this file.
+	# The theory is that they jump into the middle of the file
+	# without reading the header.
+	$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
+
 	# So file name.
 	if($modname eq "") {
 		$modname = "libc";