Add a "fork" of musl as //fusl.

fusl/src/fenv/armhf/fenv.s

Index: fusl/src/fenv/armhf/fenv.s
diff --git a/fusl/src/fenv/armhf/fenv.s b/fusl/src/fenv/armhf/fenv.s
new file mode 100644
index 0000000000000000000000000000000000000000..53307e68e1b86e03d20f132712c2e96b5f3cb9de
--- /dev/null
+++ b/fusl/src/fenv/armhf/fenv.s
@@ -0,0 +1,65 @@
+.syntax unified
+.fpu vfp
+
+.global fegetround
+.type fegetround,%function
+fegetround:
+	fmrx r0, fpscr
+	and r0, r0, #0xc00000
+	bx lr
+
+.global __fesetround
+.type __fesetround,%function
+__fesetround:
+	fmrx r3, fpscr
+	bic r3, r3, #0xc00000
+	orr r3, r3, r0
+	fmxr fpscr, r3
+	mov r0, #0
+	bx lr
+
+.global fetestexcept
+.type fetestexcept,%function
+fetestexcept:
+	and r0, r0, #0x1f
+	fmrx r3, fpscr
+	and r0, r0, r3
+	bx lr
+
+.global feclearexcept
+.type feclearexcept,%function
+feclearexcept:
+	and r0, r0, #0x1f
+	fmrx r3, fpscr
+	bic r3, r3, r0
+	fmxr fpscr, r3
+	mov r0, #0
+	bx lr
+
+.global feraiseexcept
+.type feraiseexcept,%function
+feraiseexcept:
+	and r0, r0, #0x1f
+	fmrx r3, fpscr
+	orr r3, r3, r0
+	fmxr fpscr, r3
+	mov r0, #0
+	bx lr
+
+.global fegetenv
+.type fegetenv,%function
+fegetenv:
+	fmrx r3, fpscr
+	str r3, [r0]
+	mov r0, #0
+	bx lr
+
+.global fesetenv
+.type fesetenv,%function
+fesetenv:
+	cmn r0, #1
+	moveq r3, #0
+	ldrne r3, [r0]
+	fmxr fpscr, r3
+	mov r0, #0
+	bx lr