0.8.11.4:

0.8.11.4:
	FINALLY!

	Fixed bugs related to DOUBLE-FLOAT-EPSILON on x86.  Die, bug
	#45, die a horrible death.

	... make lisp code run with the fpu set to 53-bit mantissa;
	... add code in number stack allocation to set the fpu to
		64-bit precision when calling out to C, conditional on
		new optimization quality SB-C::FLOAT-ACCURACY
		(unexported, undocumented, etc)
	... use FLOAT-ACCURACY around syscalls, since they don't
		involve the FPU.

	Also add code to allow fpu precision control in the (nominally
	private) sb-int:set-floating-point-modes.

	(this checkin fixes not only bugs #45 and #118, but also six of
	PFD's EPSILONS tests and 29 ieeefp-tests related to +, -, *, /
	and sqrt)