Add CXX API for MatchaTTS models (#1676)

c-api-examples/matcha-tts-en-c-api.c

@@ -60,7 +60,7 @@ int32_t main(int32_t argc, char *argv[]) {
       "Friends fell out often because life was changing so fast. The easiest "
       "thing in the world was to lose touch with someone.";
 
-  SherpaOnnxOfflineTts *tts = SherpaOnnxCreateOfflineTts(&config);
+  const SherpaOnnxOfflineTts *tts = SherpaOnnxCreateOfflineTts(&config);
   int32_t sid = 0;
   float speed = 1.0;  // larger -> faster in speech speed
 

c-api-examples/matcha-tts-zh-c-api.c

@@ -60,7 +60,7 @@ int32_t main(int32_t argc, char *argv[]) {
       "某某银行的副行长和一些行政领导表示，他们去过长江和长白山; "
       "经济不断增长。2024年12月31号，拨打110或者18920240511。123456块钱。";
 
-  SherpaOnnxOfflineTts *tts = SherpaOnnxCreateOfflineTts(&config);
+  const SherpaOnnxOfflineTts *tts = SherpaOnnxCreateOfflineTts(&config);
   int32_t sid = 0;
   float speed = 1.0;  // larger -> faster in speech speed
 

c-api-examples/offline-tts-c-api.c

@@ -229,7 +229,7 @@ int32_t main(int32_t argc, char *argv[]) {
     ShowUsage();
   }
 
-  SherpaOnnxOfflineTts *tts = SherpaOnnxCreateOfflineTts(&config);
+  const SherpaOnnxOfflineTts *tts = SherpaOnnxCreateOfflineTts(&config);
 
   const SherpaOnnxGeneratedAudio *audio =
       SherpaOnnxOfflineTtsGenerate(tts, text, sid, 1.0);