use darshan-gen-* scripts at make install time by default

[shanedsnyder]

In GitLab by @shanedsnyder on Sep 24, 2015, 16:24

The current Darshan releases install hand-coded mpi scripts for the IBM BG/P. We should convert to using the darshan-gen-cc.pl, darshan-gen-cxx.pl, and darshan-gen-fortran.pl scripts instead.

We should also make sure to include the XL compiler wrappers on BG/P.

[shanedsnyder]

In GitLab by @shanedsnyder on Sep 24, 2015, 16:24

We can fall back to the original MPI script if we see any unsupported mpicc-specific command line options. We can log any time this occurs so that we discover any users who might be using those options.