[Patch ,gcc/MIPS] add an build-time/runtime option to disable madd.fmt

[Sandra Loosemore]

On 12/21/2016 11:54 AM, Yunqiang Su wrote:
> By this patch, I add a build-time option ` --with-unfused-madd4=yes/no隆炉,
> and runtime option -m(no-)unfused-madd4,
> to disable generate madd.fmt instructions.

Your patch also needs a documentation change so that the new 
command-line option is listed in the GCC manual with other MIPS target 
options.

-Sandra