Fix system::archiveDir() adding 10k of padding to the end of memory output.

src/system.cpp

@@ -307,6 +307,8 @@ static void archiveDir(const std::string& archivePath, std::vector<uint8_t>* arc
 	// Open archive for writing
 	struct archive* a = archive_write_new();
 	DEFER({archive_write_free(a);});
+	// For some reason libarchive adds 10k of padding to archive_write_open() (but not archive_write_open_filename()) unless this is set to 0.
+	archive_write_set_bytes_per_block(a, 0);
 	archive_write_set_format_ustar(a);
 	archive_write_add_filter_zstd(a);
 	assert(0 <= compressionLevel && compressionLevel <= 19);