ARM Thumb targets need fmax*/fmin* intrinsics

[saleemrashid]

core::f32 and core::f64 expose max and min, but these use the fmax*/fmin* intrinsics, which aren't exposed for the Thumb targets

compiler-builtins/src/math.rs

Lines 92 to 99 in cde22bc

	// only for the thumb*-none-eabi* targets
	#[cfg(all(target_arch = "arm", target_os = "none"))]
	no_mangle! {
	// `f64 % f64`
	fn fmod(x: f64, y: f64) -> f64;
	// `f32 % f32`
	fn fmodf(x: f32, y: f32) -> f32;
	}

https://rust.godbolt.org/z/B4tB6w

#![no_std]

pub fn maxf(a: f32, b: f32) -> f32 {
    a.max(b)
}

pub fn minf(a: f32, b: f32) -> f32 {
    a.min(b)
}

pub fn max(a: f64, b: f64) -> f64 {
    a.max(b)
}

pub fn min(a: f64, b: f64) -> f64 {
    a.min(b)
}

example::maxf:
        b       fmaxf

example::minf:
        b       fminf

example::max:
        b       fmax

example::min:
        b       fmin

[jordens]

https://paste.debian.net/1168430/