case $f90 in
    g95)
        if [ "$bits" == "" ] ; then
            FFLAGS="$FFLAGS"
        else
            if [ $(uname -i) == "x86_64" ] ; then
               FFLAGS="-m$bits $FFLAGS"
            fi
        fi
        FPP=-cpp
        DEB="-g -C"
        ;;
    gfortran)
        if [ "$bits" == "" ] ; then
            FFLAGS="$FFLAGS"
        else
            if [ $(uname -i) == "x86_64" ] ; then
                FFLAGS="-m$bits $FFLAGS"
            fi
        fi
# does not work any more - FPP="-x f95-cpp-input"                               
        FPP="-cpp"
        DEB="-g -C"
        ;;
# NAG. potential FIXME: other compilers of same name need differentiator        
    f95|nagfor)
        FFLAGS="$FFLAGS -ieee=full -f2003"
        FPP=-fpp
        DEB="-g -C"
        ;;
    sunf95)
        FFLAGS="$FFLAGS -I."
        FPP=-fpp
        ;;
    ifort)
        FFLAGS="$FFLAGS"
        FPP=-fpp
        DEB="-g -check all"
        ;;
    pgf90)
       FFLAGS="$FFLAGS"
        FPP=-Mpreprocess
        DEB="-g -C"
        ;;
# CRAY Fortran                                                                  
    ftn)
        FFLAGS="$FFLAGS -I."
        FPP="-e Z"
        DEB="-g -C"
        ;;
     xlf90|xlf90_r|xlf95|xlf95_r|xlf2003|xlf2003_r)
        if [ "$bits" == "" ] ; then
            FFLAGS="$FFLAGS"
        else
            FFLAGS="-q$bits $FFLAGS"
        fi
        FPP="-qsuffix=cpp=f90"
        DEB="-g -C"
        ;;
    *)
        echo "Unsupported Fortran compiler. Aborting ..."
        exit 1