setcmp: use 'm' instead of 'a' as the assignment-allocation modifier

Support for the 'm' modifier was added to glibc starting with version 2.7,
programs should use that modifier instead of 'a'.

tools/setcmp.c

@@ -39,7 +39,7 @@ int main(int argc, const char **argv)
     int rc = 0;
     while (1) {
 	char *s1 = NULL, *s2 = NULL;
-	int n = scanf("%as %as", &s1, &s2);
+	int n = scanf("%ms %ms", &s1, &s2);
 	if (n == EOF)
 	    break;
 	assert(n == 2);