ARM assembler modules.

- introduce common modes_lcl.h;
- ctr128.c: implement additional CRYPTO_ctr128_encrypt_ctr32 interface;
- gcm128.c: add omitted ARM initialization, remove ctx.ctr;

rely on indirect call to block functions, they are not as fast as
non-consolidated routines. However, performance loss(*) is within
measurement error and consolidation advantages are considered to
outweigh it.

(*) actually one can observe performance *improvement* on e.g.
    CBC benchmarks thanks to optimization, which also becomes
    shared among ciphers.

have a uniform representation for those over all architectures, so a
little bit of hackery is needed.

Contributed by nagendra modadugu <nagendra@cs.stanford.edu>

[most importantly] put back dependencies accidentaly eliminated in
check-in #13342.

during "make errors" and thus during "make update".

Fix lots of bugs that util/ck_errf.pl can detect automatically.
Various others of these are still left to fix; that's why
"make update" will complain loudly when run now.

if $(EXHEADER) is empty.

Notified by many, solution suggested by Carson Gaspar <carson@taltos.org>

This is part of a large change submitted by Markus Friedl <markus@openbsd.org>

give it.
For 0.9.7 and up, that means util/domd needs to remove those double
dashes from the argument list when gcc is used to find the
dependencies.

handled properly.
Part of PR 75