feat(i18n): add en-US locale

include/airly/Config.h

@@ -0,0 +1,11 @@
+#ifndef AIRLY_INCLUDE_AIRLY_CONFIG_H_
+#define AIRLY_INCLUDE_AIRLY_CONFIG_H_
+
+#if !defined(THING_MODEL_B) && !defined(THING_MODEL_M)
+#error \
+    "Undefined thing model! Please define thing model via macro THING_#####_# \
+(Example: THING_MODEL_B). Supported thing models: Model B, Model M."
+#define THING_UNDEFINED
+#endif
+
+#endif  // AIRLY_INCLUDE_AIRLY_CONFIG_H_

include/airly/I18n.h

@@ -0,0 +1,22 @@
+#ifndef AIRLY_INCLUDE_AIRLY_I18N_H_
+#define AIRLY_INCLUDE_AIRLY_I18N_H_
+
+/* Compilation-time config */
+#include <airly/Config.h>
+
+#if !defined(LANG_EN_US)
+#define LANG_UNDEFINED
+#error \
+    "Undefined language! Please define language via macro LANG_##_## \
+(Example: LANG_EN_US). Available languages: en-US."
+#else
+#define LANG_DEFINED
+#endif
+
+namespace i18n {
+
+extern const char* DeviceTitle;
+
+}  // namespace i18n
+
+#endif  // AIRLY_INCLUDE_AIRLY_I18N_H_

src/airly/I18n.cc

@@ -0,0 +1,15 @@
+#include <airly/i18n.h>
+
+// -------------------------------------------------------------------------- //
+// Translations: stub
+// -------------------------------------------------------------------------- //
+#if defined(LANG_UNDEFINED)
+
+namespace i18n {
+
+const char* DeviceTitle = "";
+
+}  // namespace i18n
+
+#endif
+// -------------------------------------------------------------------------- //

src/airly/locales/en-US.cc

@@ -0,0 +1,18 @@
+#include <airly/I18n.h>
+
+/* AVR low-level */
+#include <avr/pgmspace.h>
+
+// -------------------------------------------------------------------------- //
+// Translations: common
+// -------------------------------------------------------------------------- //
+#if defined(LANG_DEFINED) && defined(THING_MODEL_B)
+
+namespace i18n {
+
+const char* DeviceTitle PROGMEM = "Airly Model B";
+
+}  // namespace i18n
+
+#endif
+// -------------------------------------------------------------------------- //