Make phoneme properties unsigned

Fixes two sanitizer warnings:

```
src/libespeak-ng/compiledata.c:2291:27: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
src/libespeak-ng/compiledata.c:2424:34: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
```

src/libespeak-ng/phoneme.h

@@ -177,23 +177,23 @@ phoneme_feature_t phoneme_feature_from_string(const char *feature);
 #define phFLAGBIT_LOCAL 31 // used during compilation
 
 // phoneme properties
-#define phUNSTRESSED   (1 << phFLAGBIT_UNSTRESSED)
-#define phVOICELESS    (1 << phFLAGBIT_VOICELESS)
-#define phVOICED       (1 << phFLAGBIT_VOICED)
-#define phSIBILANT     (1 << phFLAGBIT_SIBILANT)
-#define phNOLINK       (1 << phFLAGBIT_NOLINK)
-#define phTRILL        (1 << phFLAGBIT_TRILL)
-#define phPALATAL      (1 << phFLAGBIT_PALATAL)
-#define phBRKAFTER     (1 << phFLAGBIT_BRKAFTER)
-#define phNONSYLLABIC  (1 << phFLAGBIT_NONSYLLABIC)
-#define phLONG         (1 << phFLAGBIT_LONG)
-#define phLENGTHENSTOP (1 << phFLAGBIT_LENGTHENSTOP)
-#define phRHOTIC       (1 << phFLAGBIT_RHOTIC)
-#define phNOPAUSE      (1 << phFLAGBIT_NOPAUSE)
-#define phPREVOICE     (1 << phFLAGBIT_PREVOICE)
-#define phFLAG1        (1 << phFLAGBIT_FLAG1)
-#define phFLAG2        (1 << phFLAGBIT_FLAG2)
-#define phLOCAL        (1 << phFLAGBIT_LOCAL)
+#define phUNSTRESSED   (1U << phFLAGBIT_UNSTRESSED)
+#define phVOICELESS    (1U << phFLAGBIT_VOICELESS)
+#define phVOICED       (1U << phFLAGBIT_VOICED)
+#define phSIBILANT     (1U << phFLAGBIT_SIBILANT)
+#define phNOLINK       (1U << phFLAGBIT_NOLINK)
+#define phTRILL        (1U << phFLAGBIT_TRILL)
+#define phPALATAL      (1U << phFLAGBIT_PALATAL)
+#define phBRKAFTER     (1U << phFLAGBIT_BRKAFTER)
+#define phNONSYLLABIC  (1U << phFLAGBIT_NONSYLLABIC)
+#define phLONG         (1U << phFLAGBIT_LONG)
+#define phLENGTHENSTOP (1U << phFLAGBIT_LENGTHENSTOP)
+#define phRHOTIC       (1U << phFLAGBIT_RHOTIC)
+#define phNOPAUSE      (1U << phFLAGBIT_NOPAUSE)
+#define phPREVOICE     (1U << phFLAGBIT_PREVOICE)
+#define phFLAG1        (1U << phFLAGBIT_FLAG1)
+#define phFLAG2        (1U << phFLAGBIT_FLAG2)
+#define phLOCAL        (1U << phFLAGBIT_LOCAL)
 
 // fixed phoneme code numbers, these can be used from the program code
 #define phonCONTROL     1