Plugin: try to load all shared libraries first

Try to load all shared libraries before resolving any symbols. Fixes
problems with plugins that are linked against other shared libraries
located in LMMS' plugin directory.
(cherry picked from commit 9a4b4f3cfe)

src/core/plugin.cpp

@@ -3,7 +3,7 @@
 /*
  * plugin.cpp - implementation of plugin-class including plugin-loader
  *
- * Copyright (c) 2005-2008 Tobias Doerffel <tobydox/at/users.sourceforge.net>
+ * Copyright (c) 2005-2009 Tobias Doerffel <tobydox/at/users.sourceforge.net>
  * 
  * This file is part of Linux MultiMedia Studio - http://lmms.sourceforge.net
  *
@@ -145,10 +145,13 @@ void plugin::getDescriptorsOfAvailPlugins( QVector<descriptor> & _plugin_descs )
 	QFileInfoList list = directory.entryInfoList(
 						QStringList( "lib*.so" ) );
 #endif
-	for( QFileInfoList::iterator file = list.begin();
-						file != list.end(); ++file )
+	foreach( const QFileInfo & f, list )
+	{
+		QLibrary( f.absoluteFilePath() ).load();
+	}
+
+	foreach( const QFileInfo & f, list )
 	{
-		const QFileInfo & f = *file;
 		QLibrary plugin_lib( f.absoluteFilePath() );
 		if( plugin_lib.load() == FALSE ||
 			plugin_lib.resolve( "lmms_plugin_main" ) == NULL )