fix Makefile chmod (644)
replace MD5SUM with HASH
add PKG_MIRROR_HASH when PKG_SOURCE_PROTO:=git

(PKG_SOURCE_PROTO:=svn tarballs are not reproducible for now)

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Signed-off-by: Felix Fietkau <nbd@nbd.name>

Standard assignment is immediate expansion without any extraneous spacing, RFC822 compliant email addresses without any quotation marks and long git hashes

Signed-off-by: Stephen Walker <stephendwalker+github@gmail.com>

Signed-off-by: Norbert Summer <git@o-g.at>