Add 'xterm' option

Ref #1489

internal/config/settings.go

@@ -256,6 +256,7 @@ var DefaultGlobalOnlySettings = map[string]interface{}{
 	"sucmd":          "sudo",
 	"pluginchannels": []string{"https://raw.githubusercontent.com/micro-editor/plugin-channel/master/channel.json"},
 	"pluginrepos":    []string{},
+	"xterm":          false,
 }
 
 // a list of settings that should never be globally modified

internal/screen/screen.go

@@ -136,6 +136,12 @@ func Init() {
 		os.Setenv("TCELL_TRUECOLOR", "disable")
 	}
 
+	var oldTerm string
+	if config.GetGlobalOption("xterm").(bool) {
+		oldTerm = os.Getenv("TERM")
+		os.Setenv("TERM", "xterm-256color")
+	}
+
 	// Initilize tcell
 	var err error
 	Screen, err = tcell.NewScreen()
@@ -149,6 +155,11 @@ func Init() {
 		os.Exit(1)
 	}
 
+	// restore TERM
+	if config.GetGlobalOption("xterm").(bool) {
+		os.Setenv("TERM", oldTerm)
+	}
+
 	if config.GetGlobalOption("mouse").(bool) {
 		Screen.EnableMouse()
 	}

runtime/help/options.md

@@ -296,6 +296,13 @@ Here are the available options:
 
 	default value: `true`
 
+* `xterm`: micro will assume that the terminal it is running in conforms to
+  `xterm-256color` regardless of what the `$TERM` variable actually contains.
+   Enabling this option may cause unwanted effects if your terminal in fact
+   does not conform to the `xterm-256color` standard.
+
+    Default value: `false`
+
 ---
 
 Plugin options: all plugins come with a special option to enable or disable