Problem:    Alloc() returning "char_u *" causes a lot of type casts.
Solution:   Have it return "void *". (Mike Williams)  Define ALLOC_ONE() to
            check the simple allocations.

Problem:    Using "int" for alloc() often results in compiler warnings.
Solution:   Use "size_t" and remove type casts.  Remove alloc_check(), Vim
            only works with 32 bit ints anyway.

Problem:    Too many curly braces.
Solution:   Remove curly braces where they are not needed. (Hirohito Higashi,
            closes #3982)

Problem:    pyeval() and py3eval() leak memory.
Solution:   Do not increase the reference count twice. (Ozaki Kiichi,
            closes #4129)

Problem:    Compiler warning for Python3 interface.
Solution:   Add type cast. (Ozaki Kiichi, closes #4128, closes #4103)

Problem:    Using :python sets 'pyxversion' even when not executed.
Solution:   Check the "skip" flag. (Shane Harper, closes #3995)

Problem:    Macros for MS-Windows are inconsistent, using "32", "3264 and
            others.
Solution:   Use MSWIN for all MS-Windows builds.  Use FEAT_GUI_MSWIN for the
            GUI build. (Hirohito Higashi, closes #3932)

Problem:    Giving error messages is not flexible.
Solution:   Add semsg().  Change argument from "char_u *" to "char *", also
            for msg() and get rid of most MSG macros. (Ozaki Kiichi, closes
            #3302)  Also make emsg() accept a "char *" argument.  Get rid of
            an enormous number of type casts.

Problem:    Cannot handle binary data.
Solution:   Add the Blob type. (Yasuhiro Matsumoto, closes #3638)

Problem:    Unnecessary static function prototypes.
Solution:   Remove unnecessary prototypes.