Don't add the size parameter to the synthesize method structures as the synthesize methods don't use the size parameter.

src/libespeak-ng/espeak_command.c

 	data = &(a_command->u.my_text);
 	data->unique_identifier = ++my_current_text_id;
 	data->text = a_text;
-	data->size = size;
 	data->position = position;
 	data->position_type = position_type;
 	data->end_position = end_position;
 	data = &(a_command->u.my_mark);
 	data->unique_identifier = ++my_current_text_id;
 	data->text = a_text;
-	data->size = size;
 	data->index_mark = a_index_mark;
 	data->end_position = end_position;
 	data->flags = flags;

src/libespeak-ng/espeak_command.h

 typedef struct {
 	unsigned int unique_identifier;
 	void *text;
-	size_t size;
 	unsigned int position;
 	espeak_POSITION_TYPE position_type;
 	unsigned int end_position;
 typedef struct {
 	unsigned int unique_identifier;
 	void *text;
-	size_t size;
 	const char *index_mark;
 	unsigned int end_position;
 	unsigned int flags;