cmake recursive include dir

#	function processes each sub-directory and then adds each source file in directory
#	each function should cascade back upward in setting variables so that the bottom directory
#	adds its source first, and then the level above it adds its source and passes both up, and so on...
function( recursively_include_src which_directory return_variable )
		
	if( ${return_variable} STREQUAL "headers" )
		set( file_extension ".h" )
	else( ${return_variable} STREQUAL "headers" )
		set( file_extension ".c" )
	endif( ${return_variable} STREQUAL "headers" )
	
	#	get list of all files for this directory
	file( GLOB this_directory_all_files "${which_directory}/*" )
	
	#	get list of source from this directory
	file( GLOB this_directory_src "${which_directory}/*${file_extension}" )
	
	#	get rid of *.txt
	file( GLOB this_directory_txt "${which_directory}/*.txt" )

	#	get directories only
	if( this_directory_all_files AND this_directory_txt )
		#	remove txt from list of files to get list of directories
		list( REMOVE_ITEM this_directory_all_files ${this_directory_txt} )	
	endif( this_directory_all_files AND this_directory_txt )
	if( this_directory_all_files AND this_directory_src )
		#	remove source from list of files to get list of directories
		list( REMOVE_ITEM this_directory_all_files ${this_directory_src} )
		set( this_directory_directories ${this_directory_all_files} )
		#	for each sub-directory, call self with sub-directory as arg
		foreach( this_sub_directory ${this_directory_directories} )
			recursively_include_src( ${this_sub_directory} ${return_variable} )
		endforeach( this_sub_directory ${this_directory_directories} )
	endif( this_directory_all_files AND this_directory_src )
	
	#	add source files to ${rb_rpdb_src} in PARENT_SCOPE
	if( ${return_variable} STREQUAL "headers" )
		set( rb_rpdb_headers ${rb_rpdb_headers} ${this_directory_src} PARENT_SCOPE )
	else( ${return_variable} STREQUAL "headers" )
		set( rb_rpdb_src ${rb_rpdb_src} ${this_directory_src} PARENT_SCOPE )
	endif( ${return_variable} STREQUAL "headers" )

	set( rb_rpdb_directories ${rb_rpdb_directories} ${which_directory} PARENT_SCOPE )
	
endfunction( recursively_include_src which_directory return_variable )