template.c: main: use return instead of exit()

src/template.c

@@ -205,7 +205,7 @@ main(void)
 		printf("The block size %" PRIuMAX " is too small, should be at least "
 		       "%" PRIuMAX " bytes\n", (uintmax_t) BLOCK_SIZE_BYTES,
 		       (uintmax_t) (sizeof(SAMPLE_TYPE) / sizeof(uint8_t)));
-		exit(EXIT_FAILURE);
+		return EXIT_FAILURE;
 	}
 
 	const size_t MAX = (PRODUCT + (BLOCK_SIZE - 1)) / BLOCK_SIZE;