Update toolchain to support std::remainder

[earlephilhower]

Update newlib to enable the __ieee754_remainder(f) calls required by
std::remainder and others.

Fixes #7845

[mcspr]

#7845 successfully builds using Windows toolchain, no surprises so far

Does this need a test similar to this?

Arduino/tests/device/test_sw_newlib/test_sw_newlib.ino

Lines 27 to 31 in 39d1453

	TEST_CASE("#612 fmod and sqrt work", "[newlib]")
	{
	CHECK(fabs(fmod(2.0, 1.5) - 0.5) < 1e-6);
	CHECK(fabs(fmod(-10, -3) - (-1.0)) < 1e-5);
	}

to at least call it once

[earlephilhower]

Good idea, @mcspr . Since it's in newlib and not the core the chance of it re-breaking is low but I'll throw something in so that it at least checks linkage (the base problem here) once somewhere...