code cleanup: remove unused *constcharptr and MakeWawe2()

src/libespeak-ng/synthesize.h

 
 void SynthesizeInit(void);
 int  Generate(PHONEME_LIST *phoneme_list, int *n_ph, bool resume);
-void MakeWave2(PHONEME_LIST *p, int n_ph);
 int  SpeakNextClause(int control);
 void SetSpeed(int control);
 void SetEmbedded(int control, int value);

src/libespeak-ng/translate.h

 //     match 1 pre 2 post 0     - use common phoneme string
 //     match 1 pre 2 post 3 0   - empty phoneme string
 
-typedef const char *constcharptr;
-
 // used to mark words with the source[] buffer
 typedef struct {
 	unsigned int flags;