add an internationalization constant

gather all ENGLISH|GERMAN|CHINESE etc preprocessor hell into a single
library, so to restrict the number of targets that need to be built 8x

this still has UB/EDITOR definitions so that still needs to be dealt
with before we can build it only 8 times

i18n/CMakeLists.txt

@@ -0,0 +1,4 @@
+set(i18nSrc
+"${CMAKE_CURRENT_SOURCE_DIR}/language.cpp"
+PARENT_SCOPE
+)

i18n/include/language.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+namespace i18n {
+enum class Lang
+{
+  en,
+  de,
+  ru,
+  nl,
+  pl,
+  fr,
+  it,
+  zh
+};
+}
+
+extern const i18n::Lang g_lang;

i18n/language.cpp

@@ -0,0 +1,24 @@
+#include <language.hpp>
+
+/* FIXME: The ugliest of ugly hacks. Getting rid of this and letting language
+ * (ideally text and voice separately) be set in the options menu would be
+ * ideal. */
+const i18n::Lang g_lang{
+  #if defined(ENGLISH)
+  i18n::Lang::en
+#elif defined(CHINESE)
+  i18n::Lang::zh
+#elif defined(DUTCH)
+  i18n::Lang::nl
+#elif defined(FRENCH)
+  i18n::Lang::fr
+#elif defined(GERMAN)
+  i18n::Lang::de
+#elif defined(ITALIAN)
+  i18n::Lang::it
+#elif defined(POLISH)
+  i18n::Lang::pl
+#elif defined(RUSSIAN)
+  i18n::Lang::ru
+#endif
+};