* Infrastructure to warn about the use of deprecated preprocessor make
  variables.
* Use that infrastructure to war about MPI_CPPFLAGS.

[[Imported from SVN: r5807]]

  - Introduce autoconf substitutions DUNEMPICPPFLAGS, DUNEMPILDFLAGS and
    DUNEMPILIBS.
  - Deprecate MPI_LDFLAGS and MPI_CPPFLAGS: the automake manual recommends
    against "_" in names of such variables, MPI_LDFLAGS actually contains
    mainly libraries and simply changing MPI_LDFLAGS to MPI_LIBS will probably
    break a lot of stuff.  By deprecating MPI_CPPFLAGS it is possible to make
    the preprocessor generate a deprecation warning with instructions to
    change both MPI_CPPFLAGS and MPI_LDFLAGS (though this has yet to be
    implemented).

[[Imported from SVN: r5806]]

[[Imported from SVN: r5804]]

[[Imported from SVN: r5782]]

[[Imported from SVN: r5781]]

[[Imported from SVN: r5765]]

as a start to sort the mess, define 5 classes for variables used in the
autoconf/automake system

[[Imported from SVN: r5764]]

[[Imported from SVN: r5762]]

[[Imported from SVN: r5759]]

[[Imported from SVN: r5757]]

[[Imported from SVN: r5756]]

[[Imported from SVN: r5755]]

[[Imported from SVN: r5754]]

* implement rangecheck for finite stack (disabled when compiling with NDEBUG)
* fix lru with _GLIBCXX_DEBUG

[[Imported from SVN: r5753]]

[[Imported from SVN: r5752]]

[[Imported from SVN: r5751]]

[[Imported from SVN: r5750]]

[[Imported from SVN: r5749]]

[[Imported from SVN: r5748]]

[[Imported from SVN: r5747]]

[[Imported from SVN: r5746]]

credits for finding this issue go to the Freiburg nightly builds

[[Imported from SVN: r5745]]

[[Imported from SVN: r5744]]

sync with my version.

[[Imported from SVN: r5743]]

[[Imported from SVN: r5742]]

[[Imported from SVN: r5741]]

[[Imported from SVN: r5740]]

[[Imported from SVN: r5739]]

[[Imported from SVN: r5738]]

[[Imported from SVN: r5737]]

[[Imported from SVN: r5736]]

Substituted exit with retun in main functions. 

This prevents clever people, like myself, from complaining about memory-leak after
perfectly OK changes by fellow developers. ;)

[[Imported from SVN: r5735]]

A proper cast-to-bool is still missing.

[[Imported from SVN: r5734]]

[[Imported from SVN: r5733]]

Adhere to shared_ptr: empty constructor constructs null pointer.

[[Imported from SVN: r5732]]

Removed exit of the test program. Now the destructors are called and
there are no leaks any more.

[[Imported from SVN: r5731]]

Damn it. I forgot half the check-in.

New version without reinterpret casts. Please test!

[[Imported from SVN: r5730]]

[[Imported from SVN: r5729]]

[[Imported from SVN: r5728]]

[[Imported from SVN: r5727]]