This is a test for #12520.

They should be stored in a vector corresponding to the sample, not in a
local variable that will not be reused later.

It's more efficient and also clearer from an ownership perspective if
all objects are directly emplaced into the workspace.

ROOT::TestSupport checks info/warning/error messages during unit tests.
Previously, it would generate one global failure irrespective of how
many messages have been received.
Now, each wrong message generates a dedicated failure.

- use TString method to check name for space symbol
- fix compiler warning

TRatioPlot defines three pads named upper_pad, lower_pad and top_pad.
If single canvas contains two or more TRatioPlots, the saved C macro
declares same object variable names resulting in runtime error. This
fix add counter suffix to pads (like for histograms) resulting in
unique pad names.

After my previous work on the RooFit minimizer interfaces, it is
relatively easy to allow passing a custom gradient function to the
RooMinimizer constructor.

The interface might still evolve in the future, but this commit is still
a milestone because now we can get actual `RooFitResult` objects that
were obtained minimizing a RooFuncWrapper that wraps both the likelihood
and the gradient code.

Some helper functionality that was originally in the new RooFuncWrapper
class but that is not needed anymore with the new minimizer interface
was removed.

C++20 is currently still known broken.

This reverts commit a4c07502.

While this itself might not cause build issues, the related commit 90ffa89a does;
handle them together.

This reverts commit 90ffa89a.
It causes build failures on GCC 12.2.1 / c++17 with

```
[ 70%] Generating G__Core.cxx, ../lib/Core.pcm
In file included from input_line_7:111:
/home/linev/build/webgui/include/ROOT/RDirectoryEntry.hxx:31:33: error: missing '#include <bits/chrono.h>'; 'system_clock' must be declared before it is used
   using clock_t = std::chrono::system_clock;
                                ^
/usr/include/c++/12/bits/chrono.h:1110:12: note: declaration here is not visible
    struct system_clock
           ^
In module 'std' imported from input_line_1:1:
/usr/include/c++/12/bits/move.h:204:11: error: missing '#include <bits/chrono.h>'; 'time_point' must be defined before it is used
      _Tp __tmp = _GLIBCXX_MOVE(__a);
          ^
/home/linev/build/webgui/include/ROOT/RDirectoryEntry.hxx:89:4: note: in instantiation of function template specialization 'std::swap<std::chrono::time_point<std::chrono::system_clock, std::chrono::duration<long, std::ratio<1, 1000000000>>>>' requested here
   swap(fDate, other.fDate);
   ^
/usr/include/c++/12/bits/chrono.h:856:14: note: definition here is not reachable
      struct time_point
```

This fixes building ROOT (and installing the prerequisite python packages)
e.g. on Alma9.

Also offsets for exp labels and fStripDecimals are supported

Format code a little bit

Protect against nullptr argument
Move into implementation to provide proper documentation

Redirect calls to:
* TGaxis::SetMaxDigits()
* TGaxis::GetMaxDigits()
* TGaxis::SetExponentOffset()

Let use these configurations also in TWebCanvas, which has access to
gStyle object

This breaks the pattern used when undefining and then defining a
variable in the same flag:

$ echo | g++ -Wp,-UVAR,-DVAR=1 -c -x c++ -

Here -Wp,-UVAR,-DVAR=1 will first undefine VAR and then define it to 1

If the -Wp, is dropped, this fails:

$ echo | g++ -UVAR,-DVAR=1 -c -x c++ -
<command-line>: warning: extra tokens at end of #undef directive

Now it will only undefine VAR, but not define it. I.e.

instead of

 #undef VAR
 #define VAR 1

you get

 #undef VAR,-DVAR=1

which explains the rather cryptic warning about extra token after #undef.

This commits adds support for including analytical integrals into the
mock code-squashing test by introducing a private header that stores the
stateless implementation details.

Changes required for new functionality in RGeomViewer
Also support change visibility of physical nodes in plain JSROOT

Let fully decouple GL and hierarchy drawing.
Cross-communication performed via RGeomDescription signals

Default browsing for TGeoManager does not fit for RBrowser needs

For demo purposes one provides methods which work without direct
connection to the server like for github.io stored pages

For debugging purposes one can use protocol.json with all communication
stored there. Now one can correctly record and restore different
channels

If items where expand, correctly remember such list
and restore them

Provide extra context menus

Represent flags as checkboxes in hierarchical view.
If change visibility of logical nodes, settings for physical node
automatically reset.
Support in full and partial model

geodemo.C can be used without limitations with --web mode