[skip-changelog] Allow non-cgo builds for Darwin (#2213)

Author: cmaglie

i18n/detect_darwin.go renamed to i18n/detect_cgo_darwin.go

@@ -13,6 +13,8 @@
 // Arduino software without disclosing the source code of your own applications.
 // To purchase a commercial license, send an email to license@arduino.cc.
 
+//go:build darwin && cgo
+
 package i18n
 
 /*

i18n/detect_nocgo_darwin.go

@@ -0,0 +1,22 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+//go:build darwin && !cgo
+
+package i18n
+
+func getLocaleIdentifier() string {
+	return getLocaleIdentifierFromEnv()
+}