Matrix redistribute

See merge request elpa/elpa!31

Fixes

See merge request elpa/elpa!30

The old code crashes when calling an MPI_Allreduce. The reason is that
part of the input array (t_tmp in this case) is not initialized.

Due to an error, on systems where AVX-2 (FMA) was supported, also
the "pure" AVX kernels used FMA instructions. This has been fixed
now

If a C program needs an underscore to link against a Fortran library
append it, otherwise not

Merge branch 'matrix_redistribute' of https://gitlab.mpcdf.mpg.de/elpa/elpa into matrix_redistribute

Elpa gpu pinned

See merge request !28

This header, with C-style comments, is included in various Fortran files.
The IBM XL compiler doesn't seem to like this (at least by default).

This commit is a modificatio of the commit 4792a5a8 by Victor Yu, who
discovered the problem first