Don't check for strverscmp() on Mac OS X

It goes about checks performed by ./configure script.

Thanks to Daniel R. (r1chelt).
Don't check for WINDOW type of curses on OS X

For some reasons it can't be found.
Don't check symbols of libmagic if it's absent
Remove commented out code from the configure.in

The code removed is related to support of libcurses (non-wide version).
Check libncurses on OS X if libncursesw not found

Thanks to Daniel R. (aka r1chelt).

See also this homebrew formula:
https://github.com/mxcl/homebrew/blob/master/Library/Formula/vifm.rb
Touch aclocal.m4 file

A workaround for autoconf to ease building after pulling commits, which
change configure.in script.
Merge branch 'fix-configure-on-osx-again'