RGBDS syntax updates (#905)

New MACRO and DEF syntax

macros/code.asm

@@ -1,16 +1,16 @@
 ; Syntactic sugar macros
 
-lb: MACRO ; r, hi, lo
+MACRO lb ; r, hi, lo
 	ld \1, ((\2) & $ff) << 8 | ((\3) & $ff)
 ENDM
 
-ln: MACRO ; r, hi, lo
+MACRO ln ; r, hi, lo
 	ld \1, ((\2) & $f) << 4 | ((\3) & $f)
 ENDM
 
 ; Design patterns
 
-jumptable: MACRO
+MACRO jumptable
 	ld a, [\2]
 	ld e, a
 	ld d, 0
@@ -23,7 +23,7 @@ jumptable: MACRO
 	jp hl
 ENDM
 
-maskbits: MACRO
+MACRO maskbits
 ; masks just enough bits to cover values 0 to \1 - 1
 ; \2 is an optional shift amount
 ; e.g. "maskbits 26" becomes "and %00011111" (since 26 - 1 = %00011001)
@@ -35,20 +35,20 @@ maskbits: MACRO
 ; 	cp 26
 ; 	jr nc, .loop
 	assert 0 < (\1) && (\1) <= $100, "bitmask must be 8-bit"
-x = 1
-rept 8
-if x + 1 < (\1)
-x = (x << 1) | 1
-endc
-endr
-if _NARG == 2
-	and x << (\2)
-else
-	and x
-endc
+	DEF x = 1
+	rept 8
+		if x + 1 < (\1)
+			DEF x = (x << 1) | 1
+		endc
+	endr
+	if _NARG == 2
+		and x << (\2)
+	else
+		and x
+	endc
 ENDM
 
-calc_sine_wave: MACRO
+MACRO calc_sine_wave
 ; input: a = a signed 6-bit value
 ; output: a = d * sin(a * pi/32)
 	and %111111