On UNIX, build/unix/compiledata.sh is used, while on
Windows, cmake/scripts/compiledata.win32.in is used.

The aim of this patch is to make runtime modules "installable".

Previously, modulemap.overlay.yaml file was being generated by cmake
__only__ for build directory. So the path/to/your/build/directory was
hardcoded to modulemap.overlay.yaml and Cling was reading modulemap for
stl and libc from the build directory even if it was installed to different
location.

This was a problem for CMSSW, so in this patch I'm generating two
overlay files, one for build directory and other one for installed
directory. CMake will generate modulemap.overlay.yaml for __build__
directory from modulemap.overlay.yaml.in.build at compilation time, and
it will generate and install modulemap.overlay.yaml for __install__
directory from modulemap.overlay.yaml.install.

The script git_coreteam.py uses outdated gitstats information
from the web, while the new script uses the git shortlog from the
repository itself (with a little help of recently added .mailmap).

Instead of removing the *.pyc file in argparse2help.py,  we avoid to generate such files
by invoking argparse2help.py with option -B.

- remove trailing white spaces.

Implement an "argparse" unique description of man pages and usage for root commands. 

This error: http://cdash.cern.ch/viewBuildError.php?buildid=567476
was caused because modules couldn't merge definition of struct __pthread_internal_list

Previously, [system] was used to mark modules which were supporsed be
implicitly built by rootcling for runtime modules. This was a workaround, and it was causing
SourceLocation error in cxxmodules as it is also using the same
modulemap.

To remove the workaround, we are introducing a new convention that modules
start with ROOT_ is treated as "ROOT system modules", which can be build
implicitly.

This reverts commit dc825fc4.

* Centralise the generation of help for root command

Add argparse2help.py, add root-argparse.py, delete the old help of root, add the cmake commands needed to generate the header containing the command line options help and to generate manual page for the root command.

The python file argparse2help.py can be called with the root-argparse.py and the output name as arguments. This call will generate the header file if the output has an extension ".h" and will generate the manual page if the extension is ".1"

* Centralise the generation of help for the rest of the commands

Add cmake changes to generate headers and manual pages for rootcling hadd and hist2workspace
Delete old man pages of hadd and hist2workspace
Add commented out generation of man pages for python commands, we need to add a dependency before uncommenting them out
Add hadd rootcling hist2workspace argparse modules

* make the path compatible with windows

* review modifications

* add dependency on the input and the generation script of man pages

* remove installation of headers

* Update CMakeLists.txt

It makes no sense to generates man pages on Windows. Windows does not have the `man` command.

* Update argparse2help.py

* Update argparse2help.py

* Update argparse2help.py

* Update hadd.cxx

haddCommandLineOptionsHelp.h was not included for windows

* Update root-argparse.py

add the option --version

* Update argparse2help.py

simplified version (Thanks Bertrand !)

in ROOT6 there is only one kind of reflection information. For this
reason, also the neighbouring references to Reflex have been removed.

this is done until the present ABI issues between gcc and clang are
solved, most notably the ones concerning shared_ptrs.

* modified python files to be able to be called by argparse2help.py

* modified argparse2help to handle options with no help

* stop the scripts from running when imported

* [man,help] Add script to generate man, .h page. Use for `root`.

* Script improvements

* fix path bug

* bug fix

(cherry picked from commit 4a06e1b1c0d3da7f604f277c7dd27ed25ed8f8f1)

valarray triggers lots of symbols to be emitted during startup.

This reverts commit 86ffaecb.

This breaks runtime_cxxmodules.

This reverts commit 95812645.

This breaks the runtime_cxxmodules.

Add back the stdlib module in libc, move sys/types.h, too.

This patch should resolve a recently introduced include cycle.