Expand the libMesh dependency list (#9642)

This commit overhauls the libMesh package script in a number of ways:

* We now inherit from AutotoolsPackage.
* libMesh contains about a dozen third-party dependencies that can
  only be provided by the copy bundled with libMesh. This  patch
  enumerates all such bundled dependencies and disables all of them
  by default.
* libMesh supports compilation with external installations of boost,
  eigen, hdf5, slepc, and tbb; this patch adds all of them to
  package.py.
* libMesh will look for a few system executables (xz, bzip, gdb) by
  default. This is now disabled.
* libMesh will now used a copy of perl installed by spack instead of
  trying to find the system copy.
* Compilation with non-system MPI installations requires an additional
  flag (--with-mpi=); this has been added.

0 files changed, 0 insertions, 0 deletions