Add previously removed code (for Apple only)

Since the recipe to query the system for its library search path doesn't work on MacOSX, keep the hard-coded path for the time being, until a proper solution is found
Merge branch 'master' of https://root.cern.ch/git/root
Typo
Protection added for volumes with undefined medium
(cherry picked from commit a044372ddc4031e42f35c82c88308615e26ebac6)
Remove unused files.
Fix headers to be usable standalone.
Fix compilation error on Windows (don't use statics in inline functions)
In TClassEdit::ShortType remove default arg for __shared_ptr.
In CallFunc remove default arg for __shared_ptr.

We need to manipulate the fully qualified name to remove the default template
to properly handle the __shared_ptr case until the clang type printer properly
handles template paratemeter that are enumerator.
Add error message when argument or object are missing in CallFunc
This CMake variable might even exist.
Handle the case const __shared_ptr.

And minor performance tweak.
Use hard-coded system library path on cygwin/gcc