Default example should use host-lapack

Be more verbose in this example. If a use has lapack installed chances
are blas will be installed as well, but not vice versa.
Initial add of gnu debugger - gdb
gdb: Fail build on OSX and let user know why.
Remove hdf5 patch for cygwin (no longer needed in latest version 1.8.13).
Initial add of libtiff.
Do not use vtk's own libtiff since it fails on Darwin.
Do not add F77, F90 and FC to PETSc configure line on Darwin, since no Fortran compiler is available.
Initial add of libatomic_ops
Initial add of Boehm gc
Initial add of gzip
Initial add of patch
Initial add of binutils
Initial add of gnu awk
Initial add of libunistring
Initial add of diffutils
Put gnu sed in path when it's a build dep
Initial add of libffi
Initial add of tar
Initial add of coreutils
Initial add of bash