Implements the dylib search as specified in Apple documentation:

        http://developer.apple.com/documentation/DeveloperTools/Conceptual/
            DynamicLibraries/Articles/DynamicLibraryUsageGuidelines.html

        Before commencing the standard search, the method first checks
        the bundle's ``Frameworks`` directory if the application is running
        within a bundle (OS X .app).

def getdirs(self,libname):
        '''Implements the dylib search as specified in Apple documentation:

        http://developer.apple.com/documentation/DeveloperTools/Conceptual/
            DynamicLibraries/Articles/DynamicLibraryUsageGuidelines.html

        Before commencing the standard search, the method first checks
        the bundle's ``Frameworks`` directory if the application is running
        within a bundle (OS X .app).
        '''

        dyld_fallback_library_path = _environ_path("DYLD_FALLBACK_LIBRARY_PATH")
        if not dyld_fallback_library_path:
            dyld_fallback_library_path = [os.path.expanduser('~/lib'),
                                          '/usr/local/lib', '/usr/lib']

        dirs = []

        if '/' in libname:
            dirs.extend(_environ_path("DYLD_LIBRARY_PATH"))
        else:
            dirs.extend(_environ_path("LD_LIBRARY_PATH"))
            dirs.extend(_environ_path("DYLD_LIBRARY_PATH"))

        dirs.extend(self.other_dirs)
        dirs.append(".")
        dirs.append(os.path.dirname(__file__))

        if hasattr(sys, 'frozen') and sys.frozen == 'macosx_app':
            dirs.append(os.path.join(
                os.environ['RESOURCEPATH'],
                '..',
                'Frameworks'))

        dirs.extend(dyld_fallback_library_path)

        return dirs