UI: Fix audio ids not being stored properly

Audio ids were being stored in a map with const char pointers, thus they
were destroyed when call_once finished. To fix this, store std::strings
instead.

UI/audio-encoders.cpp

@@ -18,12 +18,12 @@ static const char *NullToEmpty(const char *str)
 	return str ? str : "";
 }
 
-static const char *EncoderName(const char *id)
+static const char *EncoderName(const std::string &id)
 {
-	return NullToEmpty(obs_encoder_get_display_name(id));
+	return NullToEmpty(obs_encoder_get_display_name(id.c_str()));
 }
 
-static map<int, const char *> bitrateMap;
+static map<int, std::string> bitrateMap;
 
 static void HandleIntProperty(obs_property_t *prop, const char *id)
 {
@@ -199,7 +199,7 @@ static void PopulateBitrateMap()
 	});
 }
 
-const map<int, const char *> &GetAACEncoderBitrateMap()
+const map<int, std::string> &GetAACEncoderBitrateMap()
 {
 	PopulateBitrateMap();
 	return bitrateMap;
@@ -211,7 +211,7 @@ const char *GetAACEncoderForBitrate(int bitrate)
 	auto res = map_.find(bitrate);
 	if (res == end(map_))
 		return NULL;
-	return res->second;
+	return res->second.c_str();
 }
 
 #define INVALID_BITRATE 10000

UI/audio-encoders.hpp

@@ -4,6 +4,6 @@
 
 #include <map>
 
-const std::map<int, const char *> &GetAACEncoderBitrateMap();
+const std::map<int, std::string> &GetAACEncoderBitrateMap();
 const char *GetAACEncoderForBitrate(int bitrate);
 int FindClosestAvailableAACBitrate(int bitrate);

UI/window-basic-settings.cpp

@@ -277,8 +277,9 @@ static void PopulateAACBitrates(initializer_list<QComboBox *> boxes)
 
 	vector<pair<QString, QString>> pairs;
 	for (auto &entry : bitrateMap)
-		pairs.emplace_back(QString::number(entry.first),
-				   obs_encoder_get_display_name(entry.second));
+		pairs.emplace_back(
+			QString::number(entry.first),
+			obs_encoder_get_display_name(entry.second.c_str()));
 
 	for (auto box : boxes) {
 		QString currentText = box->currentText();