Made Real_t default floating point type for CPU implementation and removed template parameter from TrainCpu(...).

Introduce a small function to prevent memory leaks with TSystem::ExpandPathName, which returns a string created by StrDup, that has to be deleted

"Shadow types" are transparently selected in addition to the ones
featuring unique ptrs. This allows interrogation of the type system,
autoload, autoparse and justs switches the type at streamer info
build time therewith handing a completely transparent change to the
user.

avoid double deletes under some conditions.

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

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

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

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

When building modules with clang from the trunk we need to build with gcc's
libstdc++. Apparently this can be done in clang in 2 ways:
  1. Building clang with -DGCC_INSTALL_PREFIX=$(dirname `which gcc`)/../
     This would hardcode the patch to the gcc toolchain when compiling clang.
  2. Pass on every compiler invocation --gcc-toolchain=$(dirname `which gcc`)/../
     This allows relocatability of the toolchain.

I decided to implement the second option and got stuck with implementing it in
cmake. One of the reasons was I was unable to pass --gcc-toolchain early enough
and try_compile fails at very early stages.

Finally I decided to go for the first option hardcoding the gcc toolchain path
at clang built time. This is sufficient for modules.

This commit serializes the progress I did on 2 in configure make. Now we can
configure with --gcc-toolchain in configure-make.

do not transform unique_ptrs into C ptrs when they are arguments
of templates different from stl collections.

Fix for ROOT-8046 -Python C++ class wrappers in cppyy do not report the proper name (preventing pickling)
Cope with the cases __cppname__ is not defined, try __name__ if failure.