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

fusl/src/setjmp/arm/longjmp.s

Index: fusl/src/setjmp/arm/longjmp.s
diff --git a/fusl/src/setjmp/arm/longjmp.s b/fusl/src/setjmp/arm/longjmp.s
new file mode 100644
index 0000000000000000000000000000000000000000..e28d8f31c32bec17eb454560a4fbcb50a33e1887
--- /dev/null
+++ b/fusl/src/setjmp/arm/longjmp.s
@@ -0,0 +1,40 @@
+.syntax unified
+.global _longjmp
+.global longjmp
+.type _longjmp,%function
+.type longjmp,%function
+_longjmp:
+longjmp:
+	mov ip,r0
+	movs r0,r1
+	moveq r0,#1
+	ldmia ip!, {v1,v2,v3,v4,v5,v6,sl,fp,sp,lr}
+
+	adr r1,1f
+	ldr r2,1f
+	ldr r1,[r1,r2]
+
+	tst r1,#0x260
+	beq 3f
+	tst r1,#0x20
+	beq 2f
+	ldc p2, cr4, [ip], #48
+2:	tst r1,#0x40
+	beq 2f
+	.fpu vfp
+	vldmia ip!, {d8-d15}
+	.fpu softvfp
+	.eabi_attribute 10, 0
+	.eabi_attribute 27, 0
+2:	tst r1,#0x200
+	beq 3f
+	ldcl p1, cr10, [ip], #8
+	ldcl p1, cr11, [ip], #8
+	ldcl p1, cr12, [ip], #8
+	ldcl p1, cr13, [ip], #8
+	ldcl p1, cr14, [ip], #8
+	ldcl p1, cr15, [ip], #8
+3:	bx lr
+
+.hidden __hwcap
+1:	.word __hwcap-1b