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>

Issue:
 https://github.com/openwrt/packages/issues/3191

Signed-off-by: Hirokazu MORIKAWA <morikw2@gmail.com>

---
config.c: In function 'strndup':
config.c:87:10: error: nonnull argument 's' compared to NULL [-Werror=nonnull-compare]
        if(!s)
          ^
cc1: all warnings being treated as errors
---

Signed-off-by: Hirokazu MORIKAWA <morikw2@gmail.com>

Signed-off-by: Christian Beier <cb@shoutrlabs.com>

Signed-off-by: Christian Beier <cb@shoutrlabs.com>