- Use TMath::Pi() instead of M_PI (undefined on Windows)
- Replace 'uint' with 'unsigned int'
- Fix error C2057: expected constant expression with newX and newY arrays

 - Fix error C2057: expected constant expression in several array declarations
 - Outline (move from header to source) the IsCandleScaled() and IsViolinScaled() to export them from DLL
 - In fontembedps.cxx, replace unsupported memmem() function by std::search()

an array of type T* is stored in the returned column as
vector<T>: the ownership has to be transferred to the
"extracted column".

To implement this feature, these changes were applied:
- The Take action has been restructured in order to detect the
presence of the array_view<T> type as column type. The changes
are mainly confined to transformation of types at compile times.
- The TakeHelper template and its specialisations have been modified.
Now we not only take into account the case of returned collection
equal to to vector for optimisation, but also the case where the
column in the dataset is a C style array. The specialisations of the
TakeHelper template are now 4.
In addition, a bug was fixed: the Exec function was accepting the
value of the column for a certain entry as a value, therewith potentially
triggering expensive copies.
- Some static utilities have been added in the ROOT::Internal::TDF
namespace to factor out verbose operations linked to the points mentioned
above.

 - enclose min() and max() in parentheses to prevent the following compilation errors (min and max are defined as macros in Visual Studio):
     error C2589: '(' : illegal token on right side of '::'
     error C2059: syntax error : '::'
 - implement the basic_string_view operator == (for const char *) (was somehow not resolved by Visual Studio). Thanks Axel for fixing it

Use WIN32 instead of MSVC in cmake and avoid duplication of url and md5 for LZ4 (thanks Guilherme for the feedback)

 - Add missing includes (gdk/glib) for TGWin32 dictionary generation
 - Replace use of bindexplib by CMake's built-in WINDOWS_EXPORT_ALL_SYMBOLS property
 - Replace old nmake based build by the CMake based one for builtin_freetype and builtin_pcre
 - Add support for Visual Studio for LZ4
 - Fix compilation of builtin_afterimage
 - Add a few missing compilation flags
 - Filter out the multiproc sub-directory

A fatal typo was introduced with the callbacks feature.

Right now we only generate modulemaps for the ROOT libraries which
are exposed to the user. But we also have generate dictionary
calls for dictionaries that are not exposed to the user and should
only be private (such as TBench, TMathCoreUnitDict etc.).

Right now we fail when compiling root on those dictionaries as we
don't have a modulemap for those dictionaries and we don't generate
one. This will also break tests that use the generate dictionary
call as those also don't have a modulemap now.

This patch reuses the existing CMake code for generating modulemaps
and also uses it in those cases to provide a dictionary that
rootcling can use to generate a C++ module.

This shows more explicitly that we always expect partial result objects
to exist, and we eventually pass them to user callables as references.

A TDataFrame fixture that also enables implicit MT at construction
and disables it at destruction has been added.

- test chaining of OnPartialResult[Slot] calls
- test different kind of callables
- assert that callbacks execution order is same as registration order