X3DBuffer.h is used indirectly by Graf3d and EG dictionaries. It does not
make a lot of sense to exclude it. Digging git history shows the import from
cvs so the real reason will probably remain unknown.

making Core source code independent from Graf2d dependencies.

  There are some codes compiled at the start up time. For example,
    - #include \"cling/Interpreter/RuntimeUniverse.h\"
    - #include \"cling/Interpreter/DynamicLookupRuntimeUniverse.h\"
    - namespace cling { class Interpreter; namespace runtime { Interpreter* gCling }}}
    - PrintValue
  These are passed to Cling as string and initialized at the start up time.  So I think it makes sense to reduce top-level global variables, #includes and virtual functions.

  1. Global variables
    If we break at emitModule, we can get a list of global variables and functions which are actually deserialized. These include functions, variables, STL classes and all the functions derives from them.
 I tried to change them to for example constexpr, so that it's processed at compile time.
  2. Eagerly Deserialized decls
    Thanks to @Axel 's hint and tip, we could minimize eagerly deserialized decls deserialized in ASTReader::PassInterestingDeclsToConsumer. We already removed most of eagerly deserialized decls (Some are remaining to be removed, some are hard to remove and some don't cost a lot).

  So far, we got 9.2% of cpu time improvement and 8.8% of memory improvement at start up time in release build.

  - root.exe -q -l
    - master
      cpu time = 0.09186914285714286 sec (average of 7 times)
      res  memory = 142.008 Mbytes

    - HEAD
      cpu time = 0.08337842857142856 sec
      res  memory = 129.508 Mbytes

  - hsimple.C
  Improved by 13% of cpu time and 8.5% of memory
    - master
      cpu time = 0.0954708 sec (average)
      res  memory = 142.891 Mbytes

    - HEAD
      cpu time = 0.0833258 sec
      res  memory = 130.73 Mbytes

  With modules
    - Improvement by 17.7% in cputime and 2% in memory on root.exe -q -l
    (For memory, small improvement is because most of the memory is taken by LoadModules)
    - With this patch, modules is 11.2% slower in cpu time and 6% better in residential memory.

Let store it in XML and JSON, does not affect binary I/O

Allows to use JSON and XML storage of such objects.
Does not affect binary I/O

This refactors the CMake build files to no longer manually call
the CMake functions for generating and linking the dicionairies.
One reason is to reduce boilerplate, the other is that it is now
no longer possible to have naming mismatches between the dictionary
generation arguments and linking function arguments which was causing
the race conditions we had in our build system.

This also now follows more strictly the separation between dependencies
like Math, Tree and Core and pure linking flags to external libraries.

ROOT_GENERATE_DICTIONARY allows to specify dependencies, but we currently
don't actually specify those. As we need this for getting the module
dependencies right (as we can't build missing modules on demand), we should
add those dependencies here. Then those dependencies propagate to the
rootcling invocation which will in the future also generate the C++ module
for the selected dictionary.

ClassImp is a macro defined in Rtypes.h. It can be written without trailing
semicolon. However, clang-format is based on lexing and it doesn't know at
all about preprocessors and how to expand macros. When visiting ClassImp(X)
it thinks this is not a completed entity (as it doesn't expand macros) and
considers the next line as continuation of the previous.

Inserting a semicolon fixes the issue and makes formatting with clang-format
in the ROOT codebase less tricky.

This issue is described here: https://root-forum.cern.ch/t/tcanvas-handleinput-method-perspective-vs-parallel/24086

Many headers contains redundant header guards around #include directives:

    #ifndef ROOT_TTree
    #include "TTree.h"
    #endif

This patch removes the #ifndef's around these includes as they
don't serve any pratical purpose anymore and are no longer part
of the current ROOT coding convention.

This patch also fixes the 153 typos that are contained in the
symbols of the #ifndef directives.

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

From Evgueni Tcherniaev: modify the code for WCtoNDC() and NDCtoWC() to ensure that the transformations work correctly in the case where pw and pn are the same array.

Make cannot deal with 'export *', they have to be escaped and fixed later on.

This is the recommended way of using the modules feature and should pave our way
of enabling -fmodules-local-submodules-visibility mode.

Building X3DBuffer.c (in C mode) requires X3DBuffer.h (or the module containing
it) to be able to be built in C mode.

Our two build systems can generate almost entirely a modulemap file laying out
one module per library. Due to some non-modular implementation in ROOT's core we
still need to treat some header files specially.

This patch appends modular header files to the modulemap while skipping the
predefined ones. Configure-make relates all headers that are installed in
$ROOTSYS/include to their library whereas relates only headers which are part of
library's dictionary.

  bin content to be conform to the 2D case where the surface of the boxes is
  proportional to the bin content.

Signed-off-by: Philippe Canal <pcanal@fnal.gov>

Signed-off-by: Philippe Canal <pcanal@fnal.gov>

In `TMarker3DBox` when a box marker has a size equal to zero it is not painted. Painting it produced a dot with the X11 backend.

Simplify the previous fix: No need to do the loop to find Min and Max because GetMinimum and Get Maximum do it.
This also fixes the issue mentioned here: https://root.cern.ch/phpBB3/viewtopic.php?f=3&t=21632

All files, which depend on the definition of TBuffer, should include TBuffer.h.

Fixes the modules build.

Document this backward incompatible change.