Use the stress condition values in StressCondition.

src/libespeak-ng/synthdata.c

 
 static bool StressCondition(Translator *tr, PHONEME_LIST *plist, int condition, int control)
 {
-	// condition:
-	//	0	if diminished, 1 if unstressed, 2 if not stressed, 3 if stressed, 4 if max stress
-
 	int stress_level;
 	PHONEME_LIST *pl;
 	static int condition_level[4] = { 1, 2, 4, 15 };
 		}
 	}
 
-	if (condition == 4)
+	if (condition == isMaxStress)
 		return stress_level >= pl->wordstress;
 
-	if (condition == 3) {
-		// if stressed
+	if (condition == isStressed) {
 		if (stress_level > 3)
 			return true;
 	} else {

src/libespeak-ng/synthesize.h

 #define CONDITION_IS_PHFLAG_SET 0x40
 #define CONDITION_IS_OTHER 0x80
 
-// other conditions
+// other conditions (stress)
 #define isDiminished   0
 #define isUnstressed   1
 #define isNotStressed  2
 #define isStressed     3
 #define isMaxStress    4
+
+// other conditions
 #define isBreak        5 // pause phoneme or (stop/vstop/vfric not followed by vowel or (liquid in same word))
 #define isWordStart    6
 #define isWordEnd      8