XrdSecEntity::Reset() is only available in newer versions of XRootD.

ROOT-9595 #close

by avoiding linear search (caching when needed, passing known information when available)

In case of VariableTransform.cxx, reformatted the whole file as it was
using 4 whitespaces indentation and had misleading indentation on the
bottom.

Deprecated in v6.14; plan to remove in v6.16

[net/monalisa/src/TMonaLisaWriter.cxx:956] -> [net/monalisa/src/TMonaLisaWriter.cxx:957]: (error) Iterator 'iter' used after element has been erased.
[proof/proofd/src/XrdProofdProofServMgr.cxx:4648] -> [proof/proofd/src/XrdProofdProofServMgr.cxx:4646]: (error) Iterator 'iter' used after element has been erased.

[math/minuit2/src/Minuit2Minimizer.cxx:669] -> [math/minuit2/src/Minuit2Minimizer.cxx:669]: (style) Same expression on both sides of '||'.
[math/minuit2/src/Minuit2Minimizer.cxx:736] -> [math/minuit2/src/Minuit2Minimizer.cxx:736]: (style) Same expression on both sides of '||'.
[math/minuit2/src/Minuit2Minimizer.cxx:753] -> [math/minuit2/src/Minuit2Minimizer.cxx:753]: (style) Same expression on both sides of '||'.

[tree/tree/src/TBasket.cxx:852]: (style) Redundant condition: If 'flag >= 80', the comparison 'flag' is always true.
[misc/table/src/TFileIter.cxx:467] -> [misc/table/src/TFileIter.cxx:468]: (warning) Identical condition 'thisRunNumber<runNumber', second condition is always false

[math/mathcore/src/TMath.cxx:826]: (style) Array index 'ia' is used before limits check.
[math/mathcore/src/TMath.cxx:830]: (style) Array index 'ib' is used before limits check.
[math/mathcore/src/triangle.c:15434]: (style) Array index 'aspectindex' is used before limits check.
[roofit/roofit/src/RooIntegralMorph.cxx:375]: (style) Array index 'igapHigh' is used before limits check.

[core/winnt/src/TWinNTSystem.cxx:5035]: (style) Statements following return, break, continue, goto or throw will never be executed.
[tree/treeplayer/src/TSelectorDraw.cxx:380]: (style) Statements following return, break, continue, goto or throw will never be executed.

[net/auth/src/TAuthenticate.cxx:4205]: (error) Resource leak: fd
[roofit/roofitcore/src/BidirMMapPipe.cxx:1880]: (error) Memory leak: s
[tree/tree/src/TLeaf.cxx:222]: (error) Memory leak: countname
[tree/tree/src/TLeaf.cxx:226]: (error) Memory leak: countname
[tmva/tmva/src/MethodBase.cxx:2783]: (error) Memory leak: pdfS
[tmva/tmva/src/MethodBase.cxx:2783]: (error) Memory leak: pdfB

[roofit/roofitcore/src/RooAbsArg.cxx:280]: (style) Redundant checking of STL container element existence before removing it.

[core/dictgen/src/rootcling_impl.cxx:457]: (performance) Possible inefficient checking for 'fieldSelRules' emptiness.
[core/dictgen/src/rootcling_impl.cxx:4573]: (performance) Possible inefficient checking for 'filesIncludedByLinkdef' emptiness.
[gui/canvaspainter/v7/src/TCanvasPainter.cxx:322]: (performance) Possible inefficient checking for 'fWebConn' emptiness.
[gui/canvaspainter/v7/src/TCanvasPainter.cxx:374]: (performance) Possible inefficient checking for 'fCmds' emptiness.
[gui/canvaspainter/v7/src/TCanvasPainter.cxx:419]: (performance) Possible inefficient checking for 'fWebConn' emptiness.
[gui/canvaspainter/v7/src/TCanvasPainter.cxx:475]: (performance) Possible inefficient checking for 'fWebConn' emptiness.
[gui/canvaspainter/v7/src/TCanvasPainter.cxx:587]: (performance) Possible inefficient checking for 'fCmds' emptiness.
[gui/canvaspainter/v7/src/TCanvasPainter.cxx:787]: (performance) Possible inefficient checking for 'fCmds' emptiness.
[html/src/TDocParser.cxx:684]: (performance) Possible inefficient checking for 'currentType' emptiness.
[proof/proofd/src/XrdProofdManager.cxx:804]: (performance) Possible inefficient checking for 'uwrks' emptiness.
[proof/proofd/src/XrdProofdSandbox.cxx:467]: (performance) Possible inefficient checking for 'staglst' emptiness.
[proof/proofd/src/XrdProofdSandbox.cxx:571]: (performance) Possible inefficient checking for 'actln' emptiness.
[roofit/roofitcore/src/RooSimWSTool.cxx:574]: (performance) Possible inefficient checking for 'slist' emptiness.

all the reports Prefer prefix ++/-- operators for non-primitive types

Called in TDSet::SetEntryList fixes ROOT-8165 .

Fix mostly warning C4138: '*/' found outside of comment. But also:
warning C4101: 'hProcess': unreferenced local variable
warning C4005: 'open': macro redefinition
warning C4002: too many actual parameters for macro 'open'
warning C4091: 'static ': ignored on left of '' when no variable is declared

Error in <TStatusBitsChecker>: In TProofPlayer class hierarchy, there are duplicates bits:
Error in <TStatusBitsChecker>:    Bit  16 used in TProofPlayer as kIsProcessing
Error in <TStatusBitsChecker>:    Bit  16 used in TVirtualProofPlayer as kIsSubmerger

Error in <TStatusBitsChecker>: In TProofServ class hierarchy, there are duplicates bits:
Error in <TStatusBitsChecker>:    Bit  16 used in TProofServ as kHighMemory
Error in <TStatusBitsChecker>:    Bit  16 used in TApplication as kDefaultApplication

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.

This property was renamed in CMake 2.8.12, so we now should use
the newer name on recent CMake versions. We don't need to support
the pre-2.8.12 versions of CMake because we anyway have code
that requires 3.x.

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.

This is already the case in CMake builds, adding it to make
behavior between build types more uniform. The option is not
added for ICC since it does not have such option and will
generate warnings about ignored flags. Also remove some old
unused options.

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.

gROOTMutex (equal to gInterpreterMutex) are always set at the same type as gGlobalMutex so there is no need to use R__LOCKGUARD2

Fix for coverity #61340 #61356 #61397 #61413 #61359 #44337 #54858 #54872 #61261 #62101 #62104 #56175

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>

This reverts commit 04178a28.

This is not needed anymore because cling can bridge well compiled and interpreted worlds.