Problem:    nfa_recognize_char_class() implementation is inefficient.
Solution:   Use bits in an int instead of chars in a string. (Dominique Pelle)

Problem:    New regexp matching: Using \@= and the like can be slow.
Solution:   Decide whether to first try matching the zero-wdith part or what
            follows, whatever is more likely to fail.

Problem:    Building on MS-Windows doesn't see changes in if_py_both.h.
Solution:   Add a dependency. (Ken Takata)

Problem:    Error message for os.fchdir() (Charles Peacech)
Solution:   Clear the error. (ZyX)

Problem:    Compiler warnings for unused variables.
Solution:   Put the variables inside #ifdef.

Problem:    New regexp engine: saving and restoring lastlist in the states
            takes a lot of time.
Solution:   Use a second lastlist value for the first recursive call.

Problem:    New regexp engine: too much code in one function.  Dead code.
Solution:   Move the recursive nfa_regmatch call to a separate function.
            Remove the dead code.

Problem:    New regexp engine does not handle "~".
Solution:   Add support for "~".

Problem:    New regexp engine: overhead in saving and restoring.
Solution:   Make saving and restoring list IDs faster.  Don't copy or check \z
            subexpressions when they are not used.

Problem:    Completion of ":py3do" and ":py3file" does not work after ":py3".
Solution:   Make completion work. (Taro Muraoka)

Problem:    Configure doesn't find Python 3 on Ubuntu 13.04.
Solution:   First try distutils.sysconfig. Also fix some indents.  (Ken
            Takata)

Problem:    Python: a few more memory problems.
Solution:   Add and remove Py_XDECREF(). (ZyX)

Problem:    Python: Changing directory with os.chdir() causes problems for
            Vim's notion of directories.
Solution:   Add vim.chdir() and vim.fchdir(). (ZyX)

Problem:    Python: Possible memory leaks
Solution:   Add Py_XDECREF() calls. (ZyX)

Problem:    Python: a few recently added items are not documented.
Solution:   Update the documentation. (ZyX)

Problem:    Python: popitem() was not defined in a standard way.
Solution:   Remove the argument from popitem(). (ZyX)

Problem:    Compiler warnings for shadowed variables. (Christian Brabandt)
Solution:   Rename new_state() to alloc_state().  Remove unnecessary
            declaration.

Problem:    New regexp engine: Attempts to match "^" at every character.
Solution:   Only try "^" at the start of a line.

Problem:    New regexp engine: When a sub expression is empty \1 skips a
            character.
Solution:   Make \1 try the current position when the match is emtpy.

Problem:    Can't build with regexp debugging.  NFA debug output shows wrong
            pattern.
Solution:   Fix debugging code for recent changes.  Add the pattern to the
            program.

Problem:    New regexp engine: no error when using \z1 or \z( where it does
            not work.
Solution:   Give an error message.

Problem:    New regexp engine does not support \z1 .. \z9 and \z(.
Solution:   Implement the syntax submatches.

Problem:    Tests 86 and 87 fail on MS-Windows. (Ken Takata)
Solution:   Fix platform-specific stuff. (ZyX)

Problem:    New regexp engine: \@<= and \@<! are not implemented.
Solution:   Implement look-behind matching.  Fix off-by-one error in old
            regexp engine.

Problem:    A leading star is not seen as a normal char when \{} follows.
Solution:   Save and restore the parse state properly.

Problem:    Old regexp engine accepts illegal range, new one doesn't.
Solution:   Also accept the illegal range with the new engine.

Problem:    New regexp engine: Non-greedy multi doesn't work.
Solution:   Implement \{-}.

Problem:    New regexp engine: only accepts up to \{,10}.
Solution:   Remove upper limit.  Remove dead code with NFA_PLUS.

Problem:    New regexp engine: Does not support \%^ and \%$.
Solution:   Support matching start and end of file.

Problem:    New regexp engine: Problem with \@= matching.
Solution:   Save and restore nfa_match.

Problem:    Compiler warnings on 64-bit Windows.
Solution:   Change variable types. (Mike Williams)

Problem:    Test 86 fails.
Solution:   Comment out the parts that don't work.  Make it pass on 32 bit
            systems.

Problem:    Test 87 fails.
Solution:   Fix the test for Python 3.3. (ZyX)  Make it pass on 32 bit systems.

Problem:    New regexp engine: \@! doesn't work.
Solution:   Implement the negated version of \@=.

Problem:    Python: Allocating dict the wrong way, causing a crash.
Solution:   Use py_dict_alloc(). Fix some exception problems. (ZyX)

Problem:    New regexp engine: \@= and \& don't work.
Solution:   Make these items work.  Add column info to logging.

Problem:    Compiler warning for storing a long_u in an int.
Solution:   Declare the number as an int. (Mike Williams)

Problem:    Compiler warning for printf format. (Manuel Ortega)
Solution:   Add type casts.

Problem:    New regexp engine may run out of states.
Solution:   Allocate states dynamically.  Also make the test report errors.