Make _pInfraFlag a boolean.

_pInfraFlag is only ever used in boolean contexts.

Source/items.cpp

@@ -510,9 +510,9 @@ void CalcPlrItemVals(int p, BOOL Loadgfx)
 	plr[p]._pILMaxDam = lmax;
 
 	if (iflgs & ISPL_INFRAVISION) {
-		plr[p]._pInfraFlag = 1;
+		plr[p]._pInfraFlag = TRUE;
 	} else {
-		plr[p]._pInfraFlag = 0;
+		plr[p]._pInfraFlag = FALSE;
 	}
 
 	plr[p]._pBlockFlag = FALSE;

Source/player.cpp

@@ -587,7 +587,7 @@ void CreatePlayer(int pnum, char c)
 	plr[pnum]._pFireResist = 0;
 	plr[pnum]._pLghtResist = 0;
 	plr[pnum]._pLightRad = 10;
-	plr[pnum]._pInfraFlag = 0;
+	plr[pnum]._pInfraFlag = FALSE;
 
 	if (c == PC_WARRIOR) {
 		plr[pnum]._pAblSpells = (__int64)1 << (SPL_REPAIR - 1);

structs.h

@@ -267,7 +267,7 @@ typedef struct PlayerStruct {
 	char _pFireResist;
 	char _pLghtResist;
 	int _pGold;
-	int _pInfraFlag;
+	BOOL _pInfraFlag;
 	int _pVar1;
 	int _pVar2;
 	int _pVar3;