Updated uses of the ctype function to support explict casting of the arguments

to (int)(unsigned char).

protocols.cc

@@ -132,7 +132,7 @@ static int nmap_protocols_init() {
   while(fgets(line, sizeof(line), fp)) {
     lineno++;
     p = line;
-    while(*p && isspace((int) *p))
+    while(*p && isspace((int) (unsigned char) *p))
       p++;
     if (*p == '#')
       continue;