Use the phflag bit offset constants to specify the phflag-based conditions.

src/libespeak-ng/compiledata.c

 	{ "isVStop",      0, phVSTOP },
 	{ "isVFricative", 0, phVFRICATIVE },
 
-	{ "isPalatal",  0, i_isPalatal },
-	{ "isLong",     0, i_isLong },
-	{ "isRhotic",   0, i_isRhotic },
-	{ "isSibilant", 0, i_isSibilant },
-	{ "isFlag1",    0, i_isFlag1 },
-	{ "isFlag2",    0, i_isFlag2 },
+	{ "isPalatal",  0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_PALATAL },
+	{ "isLong",     0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_LONG },
+	{ "isRhotic",   0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_RHOTIC },
+	{ "isSibilant", 0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_SIBILANT },
+	{ "isFlag1",    0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_FLAG1 },
+	{ "isFlag2",    0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_FLAG2 },
 
 	{ "isVel", 0, i_isVel },
 

src/libespeak-ng/synthdata.c

 		case 0x20:
 			// place of articulation
 			return ((ph->phflags >> 16) & 0xf) == data;
-		case 0x40:
+		case CONDITION_IS_PHFLAG_SET:
 			// is a bit set in phoneme flags
 			return (ph->phflags & (1 << data)) != 0;
 		case 0x80:

src/libespeak-ng/synthesize.h

 // place of articulation
 #define i_isVel      0x28
 
-// phflags
-#define i_isSibilant   0x45 // bit  5 in phflags
-#define i_isPalatal    0x49 // bit  9 in phflags
-#define i_isLong       0x55 // bit 21 in phflags
-#define i_isRhotic     0x57 // bit 23 in phflags
-#define i_isFlag1      0x5c
-#define i_isFlag2      0x5d
+#define CONDITION_IS_PHFLAG_SET 0x40
 
 #define i_StressLevel  0x800