ompi_setup_mpi_fortran.m4: only set BUILD_SIZEOF if happy=1

Only set OMPI_FORTRAN_BUILD_SIZEOF to 1 if $ompi_fortran_happy is also
1 (i.e., we're building the Fortran interface).  This prevents
building [p]size_f.f90 and trying to compile it if there is no Fortran
compiler, for example.

config/ompi_setup_mpi_fortran.m4

@@ -309,7 +309,8 @@ AC_DEFUN([OMPI_SETUP_MPI_FORTRAN],[
 
     # We need INTERFACE, ISO_FORTRAN_ENV, and STORAGE_SIZE() support
     # to build MPI_SIZEOF support
-    AS_IF([test $OMPI_FORTRAN_HAVE_INTERFACE -eq 1 && \
+    AS_IF([test $ompi_fortran_happy -eq 1 && \
+           test $OMPI_FORTRAN_HAVE_INTERFACE -eq 1 && \
            test $OMPI_FORTRAN_HAVE_ISO_FORTRAN_ENV -eq 1 && \
            test $OMPI_FORTRAN_HAVE_STORAGE_SIZE -eq 1],
           [OMPI_FORTRAN_BUILD_SIZEOF=1],