Move to new GitHub fork and switch to codeload tarballs.

Backported upstream patch to fix compilation.

Also update URL to fix uscan.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

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: Jacob Siverskog <jacob@teenageengineering.com>