Makefile: improve make distclean [1/1]

PD#SWPL-61282

Problem:
improve make distclean

Solution:
remove the whole output dir when no environment variables

Verify:
ad401_a113l

Signed-off-by: Kelvin Zhang <kelvin.zhang@amlogic.com>
Change-Id: Ib58dd6375b80e553d49472fdcb4be866f89a1739
1 file changed
tree: 53d37f7b4fd9187533b5ab0c731bd0d057d55425
  1. cmake/
  2. key/
  3. .gitignore
  4. build_combination.in
  5. Makefile
  6. symtable.mk