apps/musiccollection: build fix

Change-Id: Ia2d4f5b9b80d9385c60136f8f6185c820be2181b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5446
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

src/apps/musiccollection/FileMonitor.h

@@ -30,7 +30,7 @@ struct WatchedFile {
 class NodeRefComp {
 public:
 	bool
-	operator()(const node_ref& a, const node_ref& b)
+	operator()(const node_ref& a, const node_ref& b) const
 	{
 		return a.node < b.node;
 	}

src/apps/musiccollection/MusicCollectionWindow.cpp

@@ -19,6 +19,7 @@
 #include "ALMLayout.h"
 #include "ALMLayoutBuilder.h"
 
+#include <ctype.h>
 
 static int
 StringItemComp(const BListItem* first, const BListItem* second)