Switched to CMake for the faster compilation and the simpler Makefile.

Minor Makefile cleanups.

Before:

time make package/libvorbis/compile -j 12
Executed in   24.40 secs   fish           external
   usr time   21.17 secs    0.00 micros   21.17 secs
   sys time    3.05 secs  426.00 micros    3.05 secs

After:

time make package/libvorbis/compile -j 12
Executed in    9.19 secs   fish           external
   usr time   11.29 secs    0.00 micros   11.29 secs
   sys time    1.43 secs  421.00 micros    1.43 secs

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

Signed-off-by: Jan Pavlinec <jan.pavlinec@nic.cz>

Reduces library size by 0.6%

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

Resolves CVEs:
2018-5146
2017-14632
2017-14633

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

Signed-off-by: Ted Hess <thess@kitschensync.net>

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: Ian Leonard <antonlacon@gmail.com>

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

Signed-off-by: Ted Hess <thess@kitschensync.net>