# Flags to be passed through unchanged, with rationale:

      # -64, -mips[0-9]      enable 64-bit mode for the SGI compiler

      # -r[0-9][0-9]*        specify processor for the SGI compiler

      # -xarch=*, -xtarget=* enable 64-bit mode for the Sun compiler

      # +DA*, +DD*           enable 64-bit mode for the HP compiler

      # -q*                  compiler args for the IBM compiler

      # -m*, -t[45]*, -txscale* architecture-specific flags for GCC

      # -F/path              path to uninstalled frameworks, gcc on darwin

      # -p, -pg, --coverage, -fprofile-*  profiling flags for GCC

      # @file                GCC response files

      # -tp=*                Portland pgcc target processor selection

      -64|-mips[0-9]|-r[0-9][0-9]*|-xarch=*|-xtarget=*|+DA*|+DD*|-q*|-m*| \

      -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|@*|-tp=*)

        arg=`$echo "X$arg" | $Xsed -e "$sed_quote_subst"`

        compiler_flags="$compiler_flags $arg"

        ;;