[perl #121484] /m causing false negative

My recent commit d0d4464849e2b30aee8 in re_intuit_start() reduced the
scope of a 'skip if multiline' check, so that certain optimisations
weren't being unnecessarily skipped. Unfortunately it didn't reduce the
scope enough, so a vital slen-- was being skipped in the
SvTAIL-but-don't-fail case.

This commit just moves the !multiline test further down, and updates the
commentary and condition formatting a bit.
Synchronise versions in Maintainers.pl
Update ExtUtils-MakeMaker to CPAN version 6.94

  [DELTA]

6.94 Tue Mar 25 19:26:31 GMT 2014

    No changes from 6.93_01

6.93_01 Mon Mar 24 16:53:31 GMT 2014
    Bug fixes:
    * Resolved a regression in MM_Unix.pm
      (https://github.com/Perl-Toolchain-Gang/ExtUtils-MakeMaker/issues/96)
[perl #121366] avoid using an invalid SvPVX() in Perl_sv_pvn_force_flags

This would cause valgrind to complain about:

  vec($Foo, 0, 1) = 1; # for example

when $Foo was undef, since SvPVX()[1] isn't initialized until the SV is
at least a SVt_PV.

[1] well, sv_u.svu_rv, but sv_u is a union, so the same memory is
initialized.  This isn't technically legal from a C point of view,
but pointer types are compatible enough with each other for it to not
be an issue.
Deprecate /\C/

For 5.20, just say its deprecated. We'll add a warning in 5.22
and change its behaviour in 5.24.