Fix base.pm nonexistent module check with open files

Tony Cook: update MANIFEST
bump $base::VERSION
[perl #121010] Fix base.pm nonexistent module check with open files
perldelta for 6a601575dc
[perl #120670] make perl headers C++11 compatible
someone forgot to test_porting and it was me

add another strange email address to checkAUTHORS.pl
update the release schedule
correct release schedule: next dev series is 5.21
fix a POD error
[perl #89502] support for dld on Atari FreeMINT
fix some linuxisms and RETVAL warnings from xsubpp

Original patch by Alan, modified by Tony Cook to remove unused return
types.
freemint doesn't need the extra -lm -lposix either
new freemint hints file
add Alan Hourihane to AUTHORS
describe the level of FreeMINT support
[perl #89502] improved FreeMINT support
Update Scalar-List-utils to CPAN version 1.36

  [DELTA]

1.36 -- 2014/01/16 15:40:47
  [CHANGES]
   * Added Scalar::Util::unweaken()
   * Various documentation changes/updates

  [BUGFIXES]
   * Correct uses of overload operators in unit tests (RT91969)
Update known POD issues
Turn on read-only flag for some unchangeable inversion lists

These lists are read-only.  Turning on the flag may allow some
optimisations to be done, including some that may be added in the
future.
regcomp.c: Remove unnecessary variable

This variable is set and tested just once in all but one instance,
before being discarded.  In that one instance, it's tested twice.  The
underlying expression is just extracting a field from a structure.
There's no efficiency gain to using the variable, so might as well not
have it.