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>

Only use termio.h with glibc or uclibc, for musl include sys/ioctl.h and
termios.h instead.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

Signed-off-by: Steven Barth <steven@midlink.org>