[Ref] Use mpt::align_down.

git-svn-id: https://source.openmpt.org/svn/openmpt/trunk/OpenMPT@22320 56274372-70c3-4bfc-bfc3-4c3a0b034d27

soundlib/MODTools.cpp

@@ -414,7 +414,7 @@ PATTERNINDEX GetNumPatterns(FileReader &file, CSoundFile &sndFile, ORDERINDEX nu
 	// There are some WOW files with an extra byte at the end, and also a MOD file (idntmind.mod, MD5 a3af5c3e1af269e32dfb6677c41c8453, SHA1 4884717c298575f9884b2211c762bb1725f73743)
 	// where only the "official" patterns should be counted but the file also has an extra byte at the end.
 	// Since MOD files can technically not have an odd file size, we just always round the actual file size down.
-	const auto fileSize = file.GetLength() & ~FileReader::pos_type{1};
+	const auto fileSize = mpt::align_down(file.GetLength(), FileReader::pos_type{2});
 
 	if(wowSampleLen && (wowSampleLen + patternStartOffset) + numPatterns * 8 * 256 == fileSize)
 	{