(TARGET_FLOAT_RETURNS_IN_80387): New macro.

(TARGET_FLOAT_RETURNS_IN_80387): New macro.

(TARGET_SWITCHES): Add "no-80387", "no-soft-float", "fp-ret-in-387", and
"no-fp-ret-in-387".
Change no* switches to no-*.
(CONDITIONAL_REGISTER_USAGE): Make 387 regs fixed if the 387 is not used
at all.
(REG_CLASS_FROM_LETTER): Constraint letters 'f', 't' and 'u' are NO_REGS
if the 387 is not used.
(TRAMPOLINE_TEMPLATE): Use GEN_INT to generate const_int rtx.

From-SVN: r2001