Create an espeak-ng version of espeak_Synth.

src/include/espeak-ng/espeak_ng.h

 #ifndef ESPEAK_NG_H
 #define ESPEAK_NG_H
 
-#include <wchar.h>
+#include "speak_lib.h"
 
 #ifdef __cplusplus
 extern "C"
 ESPEAK_NG_API int
 espeak_ng_GetSampleRate(void);
 
+ESPEAK_NG_API espeak_ng_STATUS
+espeak_ng_Synthesize(const void *text,
+                     size_t size,
+                     unsigned int position,
+                     espeak_POSITION_TYPE position_type,
+                     unsigned int end_position,
+                     unsigned int flags,
+                     unsigned int *unique_identifier,
+                     void *user_data);
+
 ESPEAK_NG_API espeak_ng_STATUS
 espeak_ng_SpeakKeyName(const char *key_name);
 

src/libespeak-ng/espeak_api.c

 	phoneme_callback = PhonemeCallback;
 }
 
+ESPEAK_API espeak_ERROR espeak_Synth(const void *text, size_t size,
+                                     unsigned int position,
+                                     espeak_POSITION_TYPE position_type,
+                                     unsigned int end_position, unsigned int flags,
+                                     unsigned int *unique_identifier, void *user_data)
+{
+	return status_to_espeak_error(espeak_ng_Synthesize(text, size, position, position_type, end_position, flags, unique_identifier, user_data));
+}
+
 ESPEAK_API espeak_ERROR espeak_Key(const char *key_name)
 {
 	return status_to_espeak_error(espeak_ng_SpeakKeyName(key_name));

src/libespeak-ng/espeak_command.h

 
 int delete_espeak_command(t_espeak_command *the_command);
 
-espeak_ERROR sync_espeak_Synth(unsigned int unique_identifier, const void *text,
-                               unsigned int position, espeak_POSITION_TYPE position_type,
-                               unsigned int end_position, unsigned int flags, void *user_data);
+espeak_ng_STATUS sync_espeak_Synth(unsigned int unique_identifier, const void *text,
+                                   unsigned int position, espeak_POSITION_TYPE position_type,
+                                   unsigned int end_position, unsigned int flags, void *user_data);
 espeak_ERROR sync_espeak_Synth_Mark(unsigned int unique_identifier, const void *text,
                                     const char *index_mark, unsigned int end_position,
                                     unsigned int flags, void *user_data);

src/libespeak-ng/speech.c

 		ep->id.number = value;
 }
 
-espeak_ERROR sync_espeak_Synth(unsigned int unique_identifier, const void *text,
-                               unsigned int position, espeak_POSITION_TYPE position_type,
-                               unsigned int end_position, unsigned int flags, void *user_data)
+espeak_ng_STATUS sync_espeak_Synth(unsigned int unique_identifier, const void *text,
+                                   unsigned int position, espeak_POSITION_TYPE position_type,
+                                   unsigned int end_position, unsigned int flags, void *user_data)
 {
 	InitText(flags);
 	my_unique_identifier = unique_identifier;
 
 	end_character_position = end_position;
 
-	espeak_ERROR aStatus = status_to_espeak_error(Synthesize(unique_identifier, text, flags));
+	espeak_ng_STATUS aStatus = Synthesize(unique_identifier, text, flags);
 	#ifdef USE_ASYNC
 	wave_flush(my_audio);
 	#endif
 
 #pragma GCC visibility push(default)
 
-ESPEAK_API espeak_ERROR espeak_Synth(const void *text, size_t size,
-                                     unsigned int position,
-                                     espeak_POSITION_TYPE position_type,
-                                     unsigned int end_position, unsigned int flags,
-                                     unsigned int *unique_identifier, void *user_data)
+ESPEAK_NG_API espeak_ng_STATUS
+espeak_ng_Synthesize(const void *text, size_t size,
+                     unsigned int position,
+                     espeak_POSITION_TYPE position_type,
+                     unsigned int end_position, unsigned int flags,
+                     unsigned int *unique_identifier, void *user_data)
 {
-	(void)size; // unused
+	(void)size; // unused in non-async modes
 
-	espeak_ERROR a_error = EE_INTERNAL_ERROR;
 	static unsigned int temp_identifier;
 
 	if (unique_identifier == NULL)
 
 	// Try to add these 2 commands (single transaction)
 	if (c1 && c2) {
-		a_error = status_to_espeak_error(fifo_add_commands(c1, c2));
-		if (a_error != EE_OK) {
+		espeak_ng_STATUS status = fifo_add_commands(c1, c2);
+		if (status != ENS_OK) {
 			delete_espeak_command(c1);
 			delete_espeak_command(c2);
-			c1 = c2 = NULL;
 		}
-	} else {
-		delete_espeak_command(c1);
-		delete_espeak_command(c2);
+		return status;
 	}
+
+	delete_espeak_command(c1);
+	delete_espeak_command(c2);
+	return ENOMEM;
+#else
+	return sync_espeak_Synth(0, text, position, position_type, end_position, flags, user_data);
 #endif
-	return a_error;
 }
 
 ESPEAK_API espeak_ERROR espeak_Synth_Mark(const void *text, size_t size,