Added rotate24/48 in <ez80_builtin.h> alongside other missing __builtin functions. Also fixed <stdbit.h> and <bit>

Author: ZERICO2005

src/crt/i48add.src

@@ -15,4 +15,4 @@ __i48add:
 	adc hl, bc
 	pop bc
 	ex de, hl
-	ret
+	ret

src/crt/i48add_1.src

@@ -0,0 +1,19 @@
+; Performs 48-bit addition
+;
+; Returns:
+; ude:uhl = ude:uhl + 1
+
+	assume	adl=1
+
+	section	.text
+
+	public	__i48add_1
+__i48add_1:
+	inc	hl
+	add	hl, de
+	or	a, a
+	sbc	hl, de
+	ret	nz
+	; carry
+	inc	de
+	ret

src/crt/i48sub.src

@@ -16,4 +16,4 @@ __i48sub:
 	sbc hl, bc
 	pop bc
 	ex de, hl
-	ret
+	ret

src/crt/i48sub_1.src

@@ -0,0 +1,19 @@
+; Performs 48-bit subtraction
+;
+; Returns:
+; ude:uhl = ude:uhl - 1
+
+	assume	adl=1
+
+	section	.text
+
+	public	__i48sub_1
+__i48sub_1:
+	add	hl, de
+	or	a, a
+	sbc	hl, de
+	dec	hl
+	ret	nz
+	; carry
+	dec	de
+	ret