m4: update dolt

Support Google nacl, non-i*86 Apple targets and silent rules for
unsupported platforms.
Bump to 2.0.3-dev

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Revert "m4: update dolt"

This reverts commit 61b591d712839abdb2baab01c066ba7e3c896a00.
Support mingw PIC build with DOLT

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
dolt: support nacl and silent-rules on fallback

nacl doesn't use pic as does mingw.

Signed-off-by: Rafaël Carré <funman@videolan.org>
m4: enable dolt support for further apple platforms

This allows us to use it on x86_64, ppc and iOS, too.
NEWS: update

Signed-off-by: Timothy Gu <timothygu99@gmail.com>