Fixes #4169: Move r30397 to v1.7 branch (This is an old patch)

---svn-pre-commit-ignore-below---

r30397 [[BR]]
This is an old patch (r26226) from two years ago that somehow went directly into the 1.6 branch without first entering the trunk. Hence, the problem it fixed still remains in the trunk, and in the 1.7 series as a regression :-(

Thanks to Paul Hargrove for tracking it down.

RM-approved

cmr=v1.7.4:reviewer=ompi-gk1.7
Fixes #4162: Move r30375, 30376, 30377, 30378, 30379, 30384, 30385, 30386, r30387 to v1.7 branch

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r30379 [[BR]]
Add ability to selectively enable/disable Fortran bindings

Each Fortran bindings layer builds on the other.  Specifically:

 * You can build just mpif.h support
 * You can build mpif.h and "use mpi" support
 * You can build mpif.h and "use mpi" and "use mpi_f08" support

You cannot build mpif.h and "use mpi_f08" support without also
building "use mpi" support.

This new functionality adds new capabilities to the existing
--enable-fortran-mpi switch.  You can now pass the following values:

 * --enable-fortran-mpi=no or none: synonyms for --disable-fortran-mpi
   (i.e., build no Fortran bindings).
 * --enable-fortran-mpi=mpifh: build only mpif.h support
 * --enable-fortran-mpi=usempi: build mpif.h and "use mpi" support
 * --enable-fortran-mpi=usempif08: build mpif.h, "use mpi", and "use
   mpi_f08" support
 * --enable-fortran-mpi=yes or all: synonyms for --enable-fortran-mpi
   (i.e., no argument), which will attempt to build all 3 Fortran
   bindings

cmr=v1.7.4:ticket=4162

r30385 [[BR]]


r30386 [[BR]]
Better detection for user-requested Fortran bindings.

As discovered by the nightly build, r30379 broke the case where
configure does not find a fortran compiler, and no form of
--enable-mpi-fortran was specified.

This commit specifically calls out the difference between a user
specifying that they want Fortran bindings and the default "try to
compile all the Fortran bindings" cases.

cmr=v1.7.4:ticket=4162

r30387 [[BR]]
Ensure to protect the "use mpi" build properly

cmr=v1.7.4:ticket=4162