glibc commit last modifying the elf/elf.h: 3ab9b88e2ac91062b6d493fe32bd101a55006c6a
The elf.h file has been taken as is without any modification. This also
brings the GNU license header to the file which was missing before

Also fix the DT_VERNEEDED typo to DT_VERNEED, there is no elf header
called DT_VERNEEDED, but there is DT_VERNEED. The value set in the
elf-cleaner.cpp is the same as DT_VERNEED, likely indicating a typo.

Other `#define` declarations have also been removed which are now
available in the newer glibc elf/elf.h file.

There are multiple benefits of using CMake over Autotools like:
- CMake is much more modern and requires much less lines of code as
  compared to doing the same thing in autotools
- Autotools is years of bad decisions, generating a long 50k+ lines of
  bash script to generate the Makefiles definitely isn't a good idea and
  is really slow as well as makes debugging the build process very
  difficult
- Existing projects using termux-elf-cleaner using CMake should benefit
  from this.

The previous arghandling code expected args in a certain order. Switch
to using getopt instead to solve the issue.

Even with --dry-run elf-cleaner modified the given binary. Fix the
issue.

Currently elf-cleaner prints identical messages if multiple version
sections are removed. Print which section is removed as well, so that
it is easier to understand what is going on.

They are not suppose to be run, and only user needs to be able to read
them.

To make folder structure cleaner.

Also change help message from .. termux-elf-cleaner .. to just
.. elf-cleaner .., to make the tool even more general.

So that `make install` and similar will work.