Some Makefile consistency updates.

Added PKG_BUILD_PARALLEL for faster compilation.

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

Here was the first error I got:

  xstrtol-error.c:84:26: error: invalid use of undefined type 'struct
  rpl_option'

More information on this error here:
  https://www.mail-archive.com/clfs-support@lists.clfs.org/msg00297.html

I'm not sure if this is an issue in my build environment, but I believe
this is the proper fix because gzip and zile use the same option:

  ./utils/gzip/Makefile:	gl_cv_func_getopt_gnu=yes \
  ./utils/zile/Makefile:	gl_cv_func_getopt_gnu=yes \

This commit is mostly a reformat/sign-off of previous work by Dirk
Morris <dmorris@untangle.com>

Signed-off-by: Sébastien Delafond <sdelafond@gmail.com>

Update GNU diffutils to 3.6

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

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>

Compile with `-std=gnu99` instead of `-std=c99` to avoid redefining
`__attribute__` in `src/system.h`.

Fixes the following error spotted by the buildbot:

    In file included from ../lib/stdio.h:43:0,
                     from cmp.c:22:
    .../staging_dir/toolchain-arm_cortex-a9+vfpv3_gcc-4.8-linaro_musl-1.1.10_eabi/include/fortify/stdio.h: In function 'snprintf':
    .../staging_dir/toolchain-arm_cortex-a9+vfpv3_gcc-4.8-linaro_musl-1.1.10_eabi/include/fortify/stdio.h:99:2: error: invalid use of '__builtin_va_arg_pack ()'
      return __orig_snprintf(__s, __n, __f, __builtin_va_arg_pack());
      ^

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

Signed-off-by: John Crispin <blogic@openwrt.org>

Signed-off-by: Roger D <rogerdammit@gmail.com>