Before only condition value==floor(value) was checked.
But it can be tru also for very large floats or doubles.
Up to certain limit it does not make sence.
Moreover, it can produce wrong output while value large 1e200 cannot be
stored at all

This fixes that regex characters in the source directory path
cause the CMake configuration to fail with cryptic error messages.

This happens because we interpret the source directory as a regex in a
few places in our CMake code.

This is a preparation because we want to ship module configuration
files in the future in the cling resource directory (Clang VFS overlay
files and modulemaps). This means that we will need to know this path
in a few other places (e.g. where we specify the -ivfsoverlayPATH
arguments and potential -fmodule-map-file=PATH args)

It also makes this giant function a bit easier on the eyes.

Simply reuses the XXHASH implementation from the LZ4 library (also
used in the LZ4 frame format).

RScanner iterates over all decls in our AST, but with modules we
have hidden decl from unimported submodules in our AST. As we
call Sema functions on these decls which use the normal clang
lookup that respects visibility, we suddenly get mysterious
lookup failures from inside Sema when running rootcling.

This patch restricts RScanner to looking at visible decls, which
restores the original behavior where RScanner onlys sees visible decls
from included headers.

rootcling with modules can reach this method when running with
C++ modules and then starts deserializing decls without a
transaction. This adds the missing PUshTransactionRAII.

Those dictionaries also generate a C++ module, but we don't specify
as of yet the dependencies on the referenced C++ modules from ROOT.

Now happens when JS canvas want toggle log states

Later such specifier can be used to access object parts like axis.
For the moment is not relevant

Use no_root_json and no_h_json URL parameteres.
Automatically applied for webcanvas

Normally THttpServer includes current object version when 
reply on draw.htm requests. With "no_root_json" and "no_h_json" 
URL parameters one can disable this. Such functionality required 
for web canvas

Let retrieve latest canvas version even without explicit
Canvas::Modified() call

Fixes threading issues: multiple threads storing and restoring mutex state, the
stack being modified concurrently etc.

This is kosher because the locks were taken to forbid other threads from modifying state while this thread is modifying state.
But this thread will not modify any state while the user code is active; thus while that user code is active,
the mutex can be completely reset, and restored once the user code returns.

Reset() completely unlocks a locked mutex, returning a state object that allows a
subsequent call to Restore() to restore that state.