Codechange: Use std::unordered_map for NewGRF language_map.

NewGRFs only use a small subset of the available language IDs. Using an unordered_map allows only the reference languages to have space allocated.

This avoids manual new/delete of array.

src/newgrf.cpp

@@ -2644,7 +2644,12 @@ static ChangeInfoResult TownHouseChangeInfo(uint hid, int numinfo, int prop, Byt
 {
 	/* LanguageID "MAX_LANG", i.e. 7F is any. This language can't have a gender/case mapping, but has to be handled gracefully. */
 	const GRFFile *grffile = GetFileByGRFID(grfid);
-	return (grffile != nullptr && grffile->language_map != nullptr && language_id < MAX_LANG) ? &grffile->language_map[language_id] : nullptr;
+	if (grffile == nullptr) return nullptr;
+
+	auto it = grffile->language_map.find(language_id);
+	if (it == std::end(grffile->language_map)) return nullptr;
+
+	return &it->second;
 }
 
 /**
@@ -2859,8 +2864,6 @@ static ChangeInfoResult GlobalVarChangeInfo(uint gvid, int numinfo, int prop, By
 					break;
 				}
 
-				if (_cur.grffile->language_map == nullptr) _cur.grffile->language_map = new LanguageMap[MAX_LANG];
-
 				if (prop == 0x15) {
 					uint plural_form = buf->ReadByte();
 					if (plural_form >= LANGUAGE_MAX_PLURAL) {
@@ -8933,11 +8936,6 @@ GRFFile::GRFFile(const GRFConfig *config)
 	this->param_end = config->num_params;
 }
 
-GRFFile::~GRFFile()
-{
-	delete[] this->language_map;
-}
-
 /**
  * Find first cargo label that exists and is active from a list of cargo labels.
  * @param labels List of cargo labels.

src/newgrf.h

@@ -14,6 +14,7 @@
 #include "rail_type.h"
 #include "road_type.h"
 #include "fileio_type.h"
+#include "newgrf_text_type.h"
 #include "core/bitmath_func.hpp"
 #include "core/alloc_type.hpp"
 #include "core/mem_func.hpp"
@@ -140,7 +141,7 @@ struct GRFFile : ZeroedMemoryAllocator {
 
 	CanalProperties canal_local_properties[CF_END]; ///< Canal properties as set by this NewGRF
 
-	struct LanguageMap *language_map; ///< Mappings related to the languages.
+	std::unordered_map<uint8_t, LanguageMap> language_map; ///< Mappings related to the languages.
 
 	int traininfo_vehicle_pitch;  ///< Vertical offset for drawing train images in depot GUI and vehicle details
 	uint traininfo_vehicle_width; ///< Width (in pixels) of a 8/8 train vehicle in depot GUI and vehicle details
@@ -149,7 +150,6 @@ struct GRFFile : ZeroedMemoryAllocator {
 	PriceMultipliers price_base_multipliers; ///< Price base multipliers as set by the grf.
 
 	GRFFile(const struct GRFConfig *config);
-	~GRFFile();
 
 	/** Get GRF Parameter with range checking */
 	uint32_t GetParam(uint number) const