Allow periods to continue macro args

c75a953 broke my (previously-working) project that defined, via
macros, 'sizeof_.player'.
A test was added to confirm that those are indeed accepted
outside of macros.

test/asm/label-macro-arg.asm

@@ -1,3 +1,9 @@
+print: MACRO
+	printv \1
+	printt "\n"
+ENDM
+
+
 m1: MACRO
 x\1
 ENDM
@@ -14,14 +20,26 @@ ENDM
 	m1 x = 7
 	m2 2 = 8
 
-	printv x
-	printt "\n"
+	print x
+	print y
+	print xx
+	print yy
 
-	printv y
-	printt "\n"
 
-	printv xx
-	printt "\n"
+test_char: MACRO
+VAR_DEF equs "sizeof_\1something = 0"
+VAR_DEF
+sizeof_\1something = 1
+	PURGE VAR_DEF
 
-	printv yy
-	printt "\n"
+VAR_PRINT equs "printt \"sizeof_\1something equals {sizeof_\1something}\\n\""
+	VAR_PRINT
+	PURGE VAR_PRINT
+ENDM
+
+	test_char _
+	test_char @
+	test_char #
+	test_char .
+
+	test_char :