cast ptrdiff_t to int for ANSI

lang/cem/cpp.ansi/input.c

@@ -30,7 +30,7 @@ getwdir(fn)
 		return "";
 	if (p) {
 		*p = '\0';
-		fn = Salloc(fn, p - &fn[0] + 1);
+		fn = Salloc(fn, (unsigned)(p - &fn[0] + 1));
 		*p = '/';
 		return fn;
 	}