code cleanup: remove unnecessary #defines.

Found by parsing the results from this bash script:
for define in $(grep define *.h |  awk'{print $2}');
do if ! grep -q $define *.c
then
        echo "$define not found";
fi
done

src/libespeak-ng/phoneme.h

 	unsigned int length;
 } PHONEME_PROG_LOG;
 
-#define PH(c1, c2) (c2<<8)+c1          // combine two characters into an integer for phoneme name
-#define PH3(c1, c2, c3) (c3<<16)+(c2<<8)+c1
 #define PhonemeCode2(c1, c2) PhonemeCode((c2<<8)+c1)
 
 extern PHONEME_TAB_LIST phoneme_tab_list[N_PHONEME_TABS];

src/libespeak-ng/spect.h

 #define MAX_DISPLAY_FREQ 9500
 #define FRAME_HEIGHT 240
 
-#define T_ZOOMOUT  301
-#define T_ZOOMIN   302
-#define T_USEPITCHENV 303
-#define T_SAMPRATE 304
-#define T_PITCH1   305
-#define T_PITCH2   306
-#define T_DURATION 307
 #define T_AMPLITUDE 308
-#define T_AMPFRAME  309
-#define T_TIMEFRAME 310
-#define T_TIMESEQ   311
-
 #define T_AV      312
-#define T_AVP     313
-#define T_FRIC    314
-#define T_FRICBP  315
-#define T_ASPR    316
-#define T_TURB    317
-#define T_SKEW    318
-#define T_TILT    319
-#define T_KOPEN   320
 #define T_FNZ     321
 
 #define FILEID1_SPECTSEQ 0x43455053
 #define FILEID2_SPECTSEK 0x4b455354  // for Klatt sequence
 #define FILEID2_SPECTSQ2 0x32515354  // with Klatt data
 
-#define FILEID1_SPC2     0x32435053  // an old format for spectrum files
-
-#define FILEID1_PITCHENV 0x43544950
-#define FILEID2_PITCHENV 0x564e4548
-
-#define FILEID1_PRAATSEQ 0x41415250
-#define FILEID2_PRAATSEQ 0x51455354
-
 typedef struct {
 	unsigned short pitch1;
 	unsigned short pitch2;

src/libespeak-ng/synthesize.h

 #define FRFLAG_LEN_MOD         0x04 // reduce effect of length adjustment
 #define FRFLAG_BREAK_LF        0x08 // but keep f3 upwards
 #define FRFLAG_BREAK           0x10 // don't merge with next frame
-#define FRFLAG_BREAK_2         0x18 // FRFLAG_BREAK_LF or FRFLAG_BREAK
 #define FRFLAG_FORMANT_RATE    0x20 // Flag5 allow increased rate of change of formant freq
 #define FRFLAG_MODULATE        0x40 // Flag6 modulate amplitude of some cycles to give trill
 #define FRFLAG_DEFER_WAV       0x80 // Flag7 defer mixing WAV until the next frame
 #define SFLAG_SWITCHED_LANG    0x20 // this word uses phonemes from a different language
 #define SFLAG_PROMOTE_STRESS   0x40 // this unstressed word can be promoted to stressed
 
-#define SFLAG_PREV_PAUSE     0x1000 // consider previous phoneme as pause
 #define SFLAG_NEXT_PAUSE     0x2000 // consider next phoneme as pause
 
 // embedded command numbers
 #define EMBED_U    11 // audio uri
 #define EMBED_B    12 // break
 #define EMBED_F    13 // emphasis
-#define EMBED_C    14 // capital letter indication
 
 #define N_EMBEDDED_VALUES    15
 extern int embedded_value[N_EMBEDDED_VALUES];
 extern int embedded_default[N_EMBEDDED_VALUES];
 
-#define N_PEAKS2  9 // plus Notch and Fill (not yet implemented)
-#define N_MARKERS 8
-
 #define N_KLATTP   10 // this affects the phoneme data file format
 #define N_KLATTP2  14 // used in vowel files, with extra parameters for future extensions
 
 
 #define pd_FORNEXTPH     0x2
 #define pd_DONTLENGTHEN  0x4
-#define pd_REDUCELENGTHCHANGE 0x8
+
 typedef struct {
 	int pd_control;
 	int pd_param[N_PHONEME_DATA_PARAM];  // set from group 0 instructions
 #define STRESS_IS_SECONDARY     3       // secondary stress
 #define STRESS_IS_PRIMARY       4       // primary (main) stress
 #define STRESS_IS_PRIORITY      5       // replaces primary markers
-#define STRESS_IS_EMPHASIZED	6       // emphasized
 
 // other conditions
 #define isAfterStress  9

src/libespeak-ng/translate.h

 
 	int numbers;
 
-#define NUM2_THOUSANDPLEX_VAR_BITS 0x0000001e // use variant form of numbers before thousands, millions, etc.
 #define NUM2_THOUSANDS_VAR_BITS    0x000001c0 // use different forms of thousand, million, etc (M MA MB)
 #define NUM2_SWAP_THOUSANDS        0x00000200 // say "thousand" and "million" before its number, not after
 #define NUM2_ORDINAL_NO_AND        0x00000800 // don't say 'and' between tens and units for ordinal numbers