Cast `char' arguments to ctype.h functions to `unsigned char'.

These functions require their arguments to be in the range of `unsigned char'.

tests/progs/slapd-addel.c

@@ -207,7 +207,8 @@ get_add_entry( char *filename, LDAPMod ***mods )
 			if ( !( value = strchr( line, ':' ))) break;
 
 			*value++ = '\0'; 
-			while ( *value && isspace( *value )) value++;
+			while ( *value && isspace( (unsigned char) *value ))
+				value++;
 
 			addmodifyop( mods, LDAP_MOD_ADD, line, value, strlen( value ));