Desire to allocate bit in DT_PARM bitmask for DEC FORMAT compatibility purposes

[Jakub Jelinek]

On Tue, Mar 20, 2018 at 12:41:25PM -0600, Jeff Law wrote:
> This is documented in the old manuals from DEC and I've found
> essentially the same documentation in Oracle/Sun's current documentation
> as well as old MIPS documentation.   I have a high degree of confidence
> it exists in IBM's Fortran compilers as well.  In contrast Intel & PCG's
> Fortran compilers do not seem to support this extension.

My testing disagrees with the last one, at least ifort 17.0.4 handles
the default widths like this patch does with -fdec.

	Jakub