Use tags for go generate

keysyms.generated.go

@@ -1,3 +1,5 @@
+// +build portal x11
+
 package main
 
 var keysymsMap = map[rune]Keysym{

keysyms.generator.go

@@ -101,7 +101,8 @@ func main() {
 		}
 		keysymsMap[unicode] = keysym
 	}
-	content := "package main\n\n" +
+	content := "// +build portal x11\n\n" +
+		"package main\n\n" +
 		"var keysymsMap = map[rune]Keysym{\n"
 	keys := make([]rune, 0)
 	for key := range keysymsMap {

keysyms.go

@@ -1,3 +1,5 @@
+// +build portal x11
+
 /*
  *    Copyright (c) 2018 Unrud <unrud@outlook.com>
  *