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: Bruno Randolf <br1@einfach.org>

Signed-off-by: Ian Leonard <antonlacon@gmail.com>

4.1 has an important bugfix for platforms (such as ARM cns3xxx) where "char"
does not default to "signed char" and other bugfixes.

Also build with debugging enabled (-D flag) to enable debugging, the size
increase is just +336B (on platform au1000).

Signed-off-by: Bruno Randolf <br1@einfach.org>