--- OLD/xdiff/xutils.c	Thu Jan  1 00:00:00 1970
+++ NEW/xdiff/xutils.c	Thu Jan  1 00:00:00 1970
@@ -26,7 +26,7 @@
 
 #define XDL_GUESS_NLINES 256
 
-
+#define xisspace(x) isspace((unsigned char)(x))
 
 
 long xdl_bogosqrt(long n) {
@@ -192,11 +192,11 @@
 
 	if (flags & XDF_IGNORE_WHITESPACE) {
 		for (i1 = i2 = 0; i1 < s1 && i2 < s2; ) {
-			if (isspace(l1[i1]))
-				while (isspace(l1[i1]) && i1 < s1)
+			if (xisspace(l1[i1]))
+				while (xisspace(l1[i1]) && i1 < s1)
 					i1++;
-			if (isspace(l2[i2]))
-				while (isspace(l2[i2]) && i2 < s2)
+			if (xisspace(l2[i2]))
+				while (xisspace(l2[i2]) && i2 < s2)
 					i2++;
 			if (i1 < s1 && i2 < s2 && l1[i1++] != l2[i2++])
 				return 0;
@@ -204,12 +204,12 @@
 		return (i1 >= s1 && i2 >= s2);
 	} else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
 		for (i1 = i2 = 0; i1 < s1 && i2 < s2; ) {
-			if (isspace(l1[i1])) {
-				if (!isspace(l2[i2]))
+			if (xisspace(l1[i1])) {
+				if (!xisspace(l2[i2]))
 					return 0;
-				while (isspace(l1[i1]) && i1 < s1)
+				while (xisspace(l1[i1]) && i1 < s1)
 					i1++;
-				while (isspace(l2[i2]) && i2 < s2)
+				while (xisspace(l2[i2]) && i2 < s2)
 					i2++;
 			} else if (l1[i1++] != l2[i2++])
 				return 0;
@@ -218,9 +218,9 @@
 	} else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
 		for (i1 = i2 = 0; i1 < s1 && i2 < s2; ) {
 			if (l1[i1] != l2[i2]) {
-				while (i1 < s1 && isspace(l1[i1]))
+				while (i1 < s1 && xisspace(l1[i1]))
 					i1++;
-				while (i2 < s2 && isspace(l2[i2]))
+				while (i2 < s2 && xisspace(l2[i2]))
 					i2++;
 				if (i1 < s1 || i2 < s2)
 					return 0;
@@ -240,9 +240,9 @@
 	char const *ptr = *data;
 
 	for (; ptr < top && *ptr != '\n'; ptr++) {
-		if (isspace(*ptr)) {
+		if (xisspace(*ptr)) {
 			const char *ptr2 = ptr;
-			while (ptr + 1 < top && isspace(ptr[1])
+			while (ptr + 1 < top && xisspace(ptr[1])
 					&& ptr[1] != '\n')
 				ptr++;
 			if (flags & XDF_IGNORE_WHITESPACE)