git change: update configure to support 'git' detection and git 'clone' detection
checkLink: use C++ linker for checkLink if package sets self.cxx

PETSc will use the C++ linker in this case. This is needed when an
external library uses C++, but exports a C interface that we are
testing.
Merge branch 'jed/checklink-cxx' of bitbucket:petsc/petsc

* 'jed/checklink-cxx' of bitbucket:petsc/petsc:
  checkLink: use C++ linker for checkLink if package sets self.cxx
tsimpl.h: remove obsolete _TSUserOps
doc: nightlybuild fixes
etags: exclude .git
Merge branch 'balay/nightlybuild-fixes'
dmplex: doc fixes [nightlybuilds]
Merge branch 'balay/nightlybuild-fixes'
change use of --with-c-support in example usage since that function is gone

Hg-commit: 5fa85f7c41fc9d10ea37e80640bcfce99c6bd879
remove visibility flag that is passed to MPICH since it cannot handle it

Hg-commit: 2e30c021e2d79d86f1c4b7d103dd79ee189f42d0
mkl: update checks [use sequential, add -lm, skip bad-paths]
- use mkl_sequential [and not the threaded versions]
- skip non-existant guess dir combinations
- add in -lm - as some configures fail if relying on -lm at the very end of compile
- work with --with-blas-lapack-dir=[mkl,mkl/lib,mkl/lib/intel64]

Hg-commit: 0f99f418862c6099a13e6051817ae5f3b26692bf
netcdf5 - build requires hdf5 info.

Hg-commit: a3d4112fd674fc4f9d7425c3b9e009d18ebf16eb
Merge branch 'buildsystem-outgoing' of bitbucket:petsc/petsc

* 'buildsystem-outgoing' of /home/jed/petsc:
  checkLink: use C++ linker for checkLink if package sets self.cxx
  git change: update configure to support 'git' detection and git 'clone' detection
Merge subtree config/BuildSystem

* commit '07020d075efb0f818a63eafc6a8614b12f689cf1':
  netcdf5 - build requires hdf5 info.
  mkl: update checks [use sequential, add -lm, skip bad-paths] - use mkl_sequential [and not the threaded versions] - skip non-existant guess dir combinations - add in -lm - as some configures fail if relying on -lm at the very end of compile - work with --with-blas-lapack-dir=[mkl,mkl/lib,mkl/lib/intel64]
  remove visibility flag that is passed to MPICH since it cannot handle it
  change use of --with-c-support in example usage since that function is gone
  checkLink: use C++ linker for checkLink if package sets self.cxx
  git change: update configure to support 'git' detection and git 'clone' detection