'Add \'dir\' to the list of directories that will be searched for
libraries specified to \'add_library()\' and \'set_libraries()\'.  The
linker will be instructed to search for libraries in the order they
are supplied to \'add_library_dir()\' and/or \'set_library_dirs()\'.'

def add_library_dir(self, dir):

    self.library_dirs.append(dir)
