Collected all the platform-specific code from the different build folders into a new folder in src/native. Also removed support for OSX10.2

src/native/linux/juce_linux_FileChooser.cpp

@@ -0,0 +1,45 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE library - "Jules' Utility Class Extensions"
+   Copyright 2004-9 by Raw Material Software Ltd.
+
+  ------------------------------------------------------------------------------
+
+   JUCE can be redistributed and/or modified under the terms of the GNU General
+   Public License (Version 2), as published by the Free Software Foundation.
+   A copy of the license is included in the JUCE distribution, or can be found
+   online at www.gnu.org/licenses.
+
+   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  ------------------------------------------------------------------------------
+
+   To release a closed-source product which uses JUCE, commercial licenses are
+   available: visit www.rawmaterialsoftware.com/juce for more information.
+
+  ==============================================================================
+*/
+
+// (This file gets included by juce_linux_NativeCode.cpp, rather than being
+// compiled on its own).
+#ifdef JUCE_INCLUDED_FILE
+
+//==============================================================================
+void FileChooser::showPlatformDialog (OwnedArray<File>& results,
+                                      const String& title,
+                                      const File& file,
+                                      const String& filters,
+                                      bool isDirectory,
+                                      bool isSave,
+                                      bool warnAboutOverwritingExistingFiles,
+                                      bool selectMultipleFiles,
+                                      FilePreviewComponent* previewComponent)
+{
+    //xxx ain't got one!
+    jassertfalse
+}
+
+#endif