* config/i386/i386.c (override_options): Respect user disable of
        fancy 387 math, sse, mmx.
        (construct_container): Generate error if we need an sse regster
        and sse has been disabled.
        * config/i386/i386.h (TARGET_SWITCHES): Disabling sse also disables
        later sse generations.  Disabling mmx also disables 3dnow.

From-SVN: r92530