IA MCU psABI support: changes to libraries

IA MCU psABI support: changes to libraries

Patch in the bottom adds support of IA MCU psABI to libgcc (enables
soft-fp) and libdecnumber (enables it for IA MCU).

config/

	* dfp.m4 (enable_decimal_float): Also set to yes for
	i?86*-*-elfiamcu target.

gcc/

	* configure: Regenerated.

libdecnumber/

	* configure: Regenerated.

libgcc/

	* config.host: Support i[34567]86-*-elfiamcu target.
	* config/t-softfp-sfdftf: New file.
	* config/i386/32/t-iamcu: Likewise.
	* configure: Regenerated.

From-SVN: r225198