Create espeak-ng APIs for formatting espeak_ng_STATUS codes.

src/include/espeak-ng/espeak_ng.h

@@ -57,6 +57,15 @@ typedef enum {
 	ENOUTPUT_MODE_SPEAK_AUDIO = 0x0002,
 } espeak_ng_OUTPUT_MODE;
 
+ESPEAK_NG_API void
+espeak_ng_GetStatusCodeMessage(espeak_ng_STATUS status,
+                               char *buffer,
+                               size_t length);
+
+ESPEAK_NG_API void
+espeak_ng_PrintStatusCodeMessage(espeak_ng_STATUS status,
+                                 FILE *out);
+
 ESPEAK_NG_API void
 espeak_ng_InitializePath(const char *path);