They are temporary files for vim and should be ignored.

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

They are temporary files and should be ignored.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

This will generate cscope index for the source files.

Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Added comments to explain the target tags and TAGS,
also ignore the output file of ctags.

Signed-off-by: Yang Bai <hamo.by@gmail.com>

add TAGS target to Makefile to support etags.

Signed-off-by: Yang Bai <hamo.by@gmail.com>